406 Engine Build
04-21-2017, 11:26 AM
#81
Drifting
From Wallace's Website:
Todays date is 4/21/2017
Cross Sectional Area equals the minimum cross sectional area of your intake port. (length times width)
This is most times your push rod area, but not always.
For a more accurate calculation try Larry Meaux's Pipe Max.
His program is excellent and will provide a lot of info.
Pipe Max
Todays date is 4/21/2017
Cross Sectional Area equals the minimum cross sectional area of your intake port. (length times width)
This is most times your push rod area, but not always.
For a more accurate calculation try Larry Meaux's Pipe Max.
His program is excellent and will provide a lot of info.
Pipe Max
04-21-2017, 11:30 AM
#82
Drifting
Thank you...this is exactly what I thought. But this thread raised so many doubts, I was at a loss on what to do other than spend a bunch more cash. Every book out there, all the reading, advice from certain posters I have come to believe in, ALL pointed to my interpretation and to what you have validated. The bigger is better ALWAYS comes up in these threads, and it seems easy to come to that thought....but there are some, like you that seem to disagree. Its about staying focused on what RPM range a person operate in....outside of that is useless.
You are being questioned now about your cross section calculation, so I assume you are not changing your position?? Please respond to that.
I am not taking any sides on this....I need to know what I am going to end up with, and I set those parameters on the first post. Seems to me the BEST way to make the decision is see a torque per RPM graph for each of the suggested combos. Put them all on one chart. The Camquest Online dyno charts is what I used to select the cam I have. Unless I am wrong, if I have a high torque number at 2000 an it runs flat or slightly rising to 6000 RPM.....then its easy to pick. Which combo makes this happen...that is the bottom line.
As I said, could care less what happens at 5500 and above.
You are being questioned now about your cross section calculation, so I assume you are not changing your position?? Please respond to that.
I am not taking any sides on this....I need to know what I am going to end up with, and I set those parameters on the first post. Seems to me the BEST way to make the decision is see a torque per RPM graph for each of the suggested combos. Put them all on one chart. The Camquest Online dyno charts is what I used to select the cam I have. Unless I am wrong, if I have a high torque number at 2000 an it runs flat or slightly rising to 6000 RPM.....then its easy to pick. Which combo makes this happen...that is the bottom line.
As I said, could care less what happens at 5500 and above.
Last edited by StraubTech; 04-21-2017 at 11:31 AM.
04-21-2017, 01:07 PM
#84
Le Mans Master
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Thank you Chris. Your input has certainly provided a balanced opinion against what was pretty much that my 180's were worthless for a 406 engine. And considering the reputation you have, I am compelled to listen to you.
The cam you thought would work on my proposed engine had very little split in duration between inlet and exhaust. I have read the AFR heads have such good exhaust flow that it may actually penalize you to have extended exhaust duration, and the cam you proposed only has 2 degrees, versus my Comp XR270 with 6 degrees. Is this why you proposed what is almost a single pattern cam?
I understand the 108 LSA will help torque. I assume this cam will have an early closing intake valve, making compression / torque.
Also, you did not specific a static compression ratio, it looked like you missed hitting a button when typing. I would shoot for a 0.040 quench.
Would that change if I stuck with the 1-5/8 inch exhaust....and what would be the penalty if I did? Unless I can get decent money for my Stainless Works headers i.e. $750, I hate to have to buy a 1-3/4 set.....for $1000.
As for your cams, I understand they are USA made? Can you provide some details of the cam in terms of material, etc.
Thanks so much for your input.
The cam you thought would work on my proposed engine had very little split in duration between inlet and exhaust. I have read the AFR heads have such good exhaust flow that it may actually penalize you to have extended exhaust duration, and the cam you proposed only has 2 degrees, versus my Comp XR270 with 6 degrees. Is this why you proposed what is almost a single pattern cam?
I understand the 108 LSA will help torque. I assume this cam will have an early closing intake valve, making compression / torque.
Also, you did not specific a static compression ratio, it looked like you missed hitting a button when typing. I would shoot for a 0.040 quench.
Would that change if I stuck with the 1-5/8 inch exhaust....and what would be the penalty if I did? Unless I can get decent money for my Stainless Works headers i.e. $750, I hate to have to buy a 1-3/4 set.....for $1000.
As for your cams, I understand they are USA made? Can you provide some details of the cam in terms of material, etc.
Thanks so much for your input.
04-21-2017, 01:10 PM
#85
Le Mans Master
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Bottom Line
From Straub - On the math. We use the pinch in each head, the smallest area of the runner, to calculate. Wallace's even references for more accurate math use Pipe Max. I'll stand by what we use for math as we can back it up at the track.[/QUOTE]
SO, bottom line, the AFR 180 cross sectional area of 1.92 is good enough for a 406 at 5800 RPM. And above that it will restrict flow, reducing HP etc.......! Fine with me.
I have often thought that producing great power (torque) at higher RPM is like the amateur way to do it. Anyone can just bury the pedal and let the RPM wind up on a big head engine.......just like crotch rocket motorcycles. I think it takes a lot more talent and knowledge to produce the same power (torque) at lower RPMs.....like Harley Davidson always has. NOTE: I get it, the crotch rocket bikes, and the big head cars will go FASTER, i.e. TOP SPEED, but doing 100 mph plus on my Harley, or my car, is not something I care about. I drive on the streets, not on the track.
What all this comes down to is this.....when I put the car in first gear and start pushing the gas pedal....I want the car to move forward NOW, not after it winds up the whole way to 5000 RPM. Then when I shift into second gear, the RPM drops to 2000 RPM, and I push the gas pedal down.....and the car launches forward....immediately, not after it gets the whole way to 5000 RPM., same with third gear. By now I should easily be a 55-60 mph, so four gear is just to cruise in. Needing to wind the motor up to 5000 RPM to get the car to move just makes a bunch of noise, and makes me feel like the motor is gutless. This is how my 350 feels to me. No doubt that once I get to 4500 RPM, the forward movement finally starts getting me excited, but it is still disappointing that I can't get pushed back in the seat till then, which is usually about the time that I am going fast enough for the street and I have to shift into 4 speed cruise.
What I want is big block feel. Just like my Harley.
SO, bottom line, the AFR 180 cross sectional area of 1.92 is good enough for a 406 at 5800 RPM. And above that it will restrict flow, reducing HP etc.......! Fine with me.
I have often thought that producing great power (torque) at higher RPM is like the amateur way to do it. Anyone can just bury the pedal and let the RPM wind up on a big head engine.......just like crotch rocket motorcycles. I think it takes a lot more talent and knowledge to produce the same power (torque) at lower RPMs.....like Harley Davidson always has. NOTE: I get it, the crotch rocket bikes, and the big head cars will go FASTER, i.e. TOP SPEED, but doing 100 mph plus on my Harley, or my car, is not something I care about. I drive on the streets, not on the track.
What all this comes down to is this.....when I put the car in first gear and start pushing the gas pedal....I want the car to move forward NOW, not after it winds up the whole way to 5000 RPM. Then when I shift into second gear, the RPM drops to 2000 RPM, and I push the gas pedal down.....and the car launches forward....immediately, not after it gets the whole way to 5000 RPM., same with third gear. By now I should easily be a 55-60 mph, so four gear is just to cruise in. Needing to wind the motor up to 5000 RPM to get the car to move just makes a bunch of noise, and makes me feel like the motor is gutless. This is how my 350 feels to me. No doubt that once I get to 4500 RPM, the forward movement finally starts getting me excited, but it is still disappointing that I can't get pushed back in the seat till then, which is usually about the time that I am going fast enough for the street and I have to shift into 4 speed cruise.
What I want is big block feel. Just like my Harley.
Last edited by Torqued Off; 04-21-2017 at 01:27 PM.
04-21-2017, 01:25 PM
#86
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St. Jude Donor '05
your 1-5/8 should cover the exh port of the 180 head
Dont think youll give up much of anything at all til you get some rpm to it at that point youll have to decide if you ned more and if its worth 1000....probably not. Everyone thinks they need giant headers exhaust and a dominator.
A 406 with Chris cam and that head will rip the tires to shreds whenever you want;the ideal combo is the one that works for you not what the internet says
Hell mines WAY far from textbook perfect most would hate it but works for me.
Dont think youll give up much of anything at all til you get some rpm to it at that point youll have to decide if you ned more and if its worth 1000....probably not. Everyone thinks they need giant headers exhaust and a dominator.
A 406 with Chris cam and that head will rip the tires to shreds whenever you want;the ideal combo is the one that works for you not what the internet says
Hell mines WAY far from textbook perfect most would hate it but works for me.
Last edited by cv67; 04-21-2017 at 01:26 PM.
04-21-2017, 04:16 PM
#87
Le Mans Master
Thank you Chris. Your input has certainly provided a balanced opinion against what was pretty much that my 180's were worthless for a 406 engine. And considering the reputation you have, I am compelled to listen to you.
The cam you thought would work on my proposed engine had very little split in duration between inlet and exhaust. I have read the AFR heads have such good exhaust flow that it may actually penalize you to have extended exhaust duration, and the cam you proposed only has 2 degrees, versus my Comp XR270 with 6 degrees. Is this why you proposed what is almost a single pattern cam?
I understand the 108 LSA will help torque. I assume this cam will have an early closing intake valve, making compression / torque.
Also, you did not specific a static compression ratio, it looked like you missed hitting a button when typing. I would shoot for a 0.040 quench.
Would that change if I stuck with the 1-5/8 inch exhaust....and what would be the penalty if I did? Unless I can get decent money for my Stainless Works headers i.e. $750, I hate to have to buy a 1-3/4 set.....for $1000.
As for your cams, I understand they are USA made? Can you provide some details of the cam in terms of material, etc.
Thanks so much for your input.
The cam you thought would work on my proposed engine had very little split in duration between inlet and exhaust. I have read the AFR heads have such good exhaust flow that it may actually penalize you to have extended exhaust duration, and the cam you proposed only has 2 degrees, versus my Comp XR270 with 6 degrees. Is this why you proposed what is almost a single pattern cam?
I understand the 108 LSA will help torque. I assume this cam will have an early closing intake valve, making compression / torque.
Also, you did not specific a static compression ratio, it looked like you missed hitting a button when typing. I would shoot for a 0.040 quench.
Would that change if I stuck with the 1-5/8 inch exhaust....and what would be the penalty if I did? Unless I can get decent money for my Stainless Works headers i.e. $750, I hate to have to buy a 1-3/4 set.....for $1000.
As for your cams, I understand they are USA made? Can you provide some details of the cam in terms of material, etc.
Thanks so much for your input.
I have a single pattern 108 LSA cam in my 350 with the same heads, 10.6 CR, .038 squish with d-dish pistons and it runs very well IMO.
I do have side pipes though and the primaries on those are 1 7/8". This cam does not tolerate back pressure well.
I'm surprised he didn't recommend a 107 lsa or even 106 for the 408, but Chris knows his stuff as he has proven many times here.
I wouldn't say I have BB torque by any means, but good torque for a 350. Mine is a TH350 auto with a 3000 stall torque converter, so not a fair comparison to a 4 speed manual. However when I mash the go pedal from a stop I get lots of wheel spin, even at 30 MPH is still squirms with 255 wide tires, so there is adequate torque from this little mouse.
On top of that it gets 18 MPG.
It's on par, a dead heat, with my 2013 Dodge challenger with it's 373 net HP, which would puts it in the range of 440 gross HP. It suits me fine at this time.
04-21-2017, 05:41 PM
#88
Le Mans Master
Looking at your engine specs here is what I see as potential torque reducers in the build.
The zz4 claims 10:1 CR with 58 cc chambers. The only way to get that is with a .040 squish and 13cc dish pistons. Looking at those piston they are the same ones that were used in my L-48. I cc'd those pistons out to 17 cc's. So in reality the zz4 has a CR of 9.59 with the 58 cc heads.
http://www.chevrolet.com/content/dam...e-24502609.pdf
Now add the 65 cc AFR's with a .015" gasket and a piston .025" in the hole at TDC and you get a CR of 8.93:1. So the engine is not likely at 10:1 CR. The dynamic CR is 7.36 with the cam in use.
With the split duration cam currently in use on the AFR head I believe it's likely that the head is going to be over scavenged. This sends some of the fresh intake charge down the exhaust pipe during the overlap period, resulting in a loss of torque.
The 110 LSA is going to have a lower TQ production over a lower duration 108 cam.
The RPM intake is for just that, RPM.
If more torque is desired below peak torque and maybe a lower peak torque RPM then an intake without a cut down divider is going to be better. Also a 4 hole spacer will provide more vacuum signal to the carb and a snappier throttle response, at least that has been my experience thus far.
35* of timing might be too much for the AFR head. Experiment with less. I'm using 32* currently with good results.
I'm not one of the requested posters in you first post and I'm by no means an expert on these things. I have been tweaking my 350 for the last 7 years however, and have learned plenty about it so far. For whatever that's worth.
The zz4 claims 10:1 CR with 58 cc chambers. The only way to get that is with a .040 squish and 13cc dish pistons. Looking at those piston they are the same ones that were used in my L-48. I cc'd those pistons out to 17 cc's. So in reality the zz4 has a CR of 9.59 with the 58 cc heads.
http://www.chevrolet.com/content/dam...e-24502609.pdf
Now add the 65 cc AFR's with a .015" gasket and a piston .025" in the hole at TDC and you get a CR of 8.93:1. So the engine is not likely at 10:1 CR. The dynamic CR is 7.36 with the cam in use.
With the split duration cam currently in use on the AFR head I believe it's likely that the head is going to be over scavenged. This sends some of the fresh intake charge down the exhaust pipe during the overlap period, resulting in a loss of torque.
The 110 LSA is going to have a lower TQ production over a lower duration 108 cam.
The RPM intake is for just that, RPM.
If more torque is desired below peak torque and maybe a lower peak torque RPM then an intake without a cut down divider is going to be better. Also a 4 hole spacer will provide more vacuum signal to the carb and a snappier throttle response, at least that has been my experience thus far.
35* of timing might be too much for the AFR head. Experiment with less. I'm using 32* currently with good results.
I'm not one of the requested posters in you first post and I'm by no means an expert on these things. I have been tweaking my 350 for the last 7 years however, and have learned plenty about it so far. For whatever that's worth.
04-21-2017, 06:16 PM
#89
Le Mans Master
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Response
Looking at your engine specs here is what I see as potential torque reducers in the build.
The zz4 claims 10:1 CR with 58 cc chambers. The only way to get that is with a .040 squish and 13cc dish pistons. Looking at those piston they are the same ones that were used in my L-48. I cc'd those pistons out to 17 cc's. So in reality the zz4 has a CR of 9.59 with the 58 cc heads.
http://www.chevrolet.com/content/dam...e-24502609.pdf
Now add the 65 cc AFR's with a .015" gasket and a piston .025" in the hole at TDC and you get a CR of 8.93:1. So the engine is not likely at 10:1 CR. The dynamic CR is 7.36 with the cam in use.
With the split duration cam currently in use on the AFR head I believe it's likely that the head is going to be over scavenged. This sends some of the fresh intake charge down the exhaust pipe during the overlap period, resulting in a loss of torque.
The 110 LSA is going to have a lower TQ production over a lower duration 108 cam.
The RPM intake is for just that, RPM.
If more torque is desired below peak torque and maybe a lower peak torque RPM then an intake without a cut down divider is going to be better. Also a 4 hole spacer will provide more vacuum signal to the carb and a snappier throttle response, at least that has been my experience thus far.
35* of timing might be too much for the AFR head. Experiment with less. I'm using 32* currently with good results.
I'm not one of the requested posters in you first post and I'm by no means an expert on these things. I have been tweaking my 350 for the last 7 years however, and have learned plenty about it so far. For whatever that's worth.
The zz4 claims 10:1 CR with 58 cc chambers. The only way to get that is with a .040 squish and 13cc dish pistons. Looking at those piston they are the same ones that were used in my L-48. I cc'd those pistons out to 17 cc's. So in reality the zz4 has a CR of 9.59 with the 58 cc heads.
http://www.chevrolet.com/content/dam...e-24502609.pdf
Now add the 65 cc AFR's with a .015" gasket and a piston .025" in the hole at TDC and you get a CR of 8.93:1. So the engine is not likely at 10:1 CR. The dynamic CR is 7.36 with the cam in use.
With the split duration cam currently in use on the AFR head I believe it's likely that the head is going to be over scavenged. This sends some of the fresh intake charge down the exhaust pipe during the overlap period, resulting in a loss of torque.
The 110 LSA is going to have a lower TQ production over a lower duration 108 cam.
The RPM intake is for just that, RPM.
If more torque is desired below peak torque and maybe a lower peak torque RPM then an intake without a cut down divider is going to be better. Also a 4 hole spacer will provide more vacuum signal to the carb and a snappier throttle response, at least that has been my experience thus far.
35* of timing might be too much for the AFR head. Experiment with less. I'm using 32* currently with good results.
I'm not one of the requested posters in you first post and I'm by no means an expert on these things. I have been tweaking my 350 for the last 7 years however, and have learned plenty about it so far. For whatever that's worth.
I have read enough now to agree that the split duration cam is not the best choice for an AFR head. I also need more lift, and as recommended, I should use less LSA.
My Quadrajet Performer RPM does NOT have a cut down divider. So not sure what you are talking about.
As for timing, you think I have too much advance?? I am getting no pinging....of course, if my CR is as low as you are suggesting, then I probably would not.
Very interesting.
04-21-2017, 06:27 PM
#90
Le Mans Master
My Quadrajet Performer RPM does NOT have a cut down divider. So not sure what you are talking about.
https://www.summitracing.com/parts/edl-7166/overview/
In either case it's my understanding that the RPM intakes have a range of 1500 to 6500 vs the non-RPM versions with idle to 5500 RPM.
Higher RPM range performance usually sacrifices lower RPM performance to get that high RPM performance.
04-21-2017, 06:41 PM
#91
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I back filled the Summit Compression Ratio calculator with zz4 specs, and it shows 10:1 CR, and piston cc at 5 cc. The ZZ4 uses a .051 head gasket. So, if that is correct at piston volume of 5cc, then my engine is 10:1.
Can anyone contribute to this. The question is, does a ZZ4 piston have a 5 cc volume? The pistons are pure flat top with only four small valve reliefs. They are not dished ....pure flat top, as in the picture.
Last edited by Torqued Off; 04-21-2017 at 07:23 PM.
04-21-2017, 06:44 PM
#92
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7104
Ok, bad assumption I thought you were using something like this;
https://www.summitracing.com/parts/edl-7166/overview/
In either case it's my understanding that the RPM intakes have a range of 1500 to 6500 vs the non-RPM versions with idle to 5500 RPM.
Higher RPM range performance usually sacrifices lower RPM performance to get that high RPM performance.
https://www.summitracing.com/parts/edl-7166/overview/
In either case it's my understanding that the RPM intakes have a range of 1500 to 6500 vs the non-RPM versions with idle to 5500 RPM.
Higher RPM range performance usually sacrifices lower RPM performance to get that high RPM performance.
Mine is PN 7104. I understand what you are saying, but thought a straight Performer would be very restrictive to the good flow of a 180 AFR. ??
04-21-2017, 11:06 PM
#93
Le Mans Master
If I put the numbers you gave and assume a zero deck? then to get a 10:1 cr the Pistons are 11 cc's (which seems big) assuming the heads they use for that computation are 58 cc's with a .051 gasket.
I would agree that the 2101 or similar performer would be restrictive, just after what rpm is the question, maybe not until 5500? I can't say.
There are trade offs for sure. RPM and higher hp or torque and lower rpm.
I ported out my 2101 to try to get the best of both worlds. I also use a 4 hole spacer for low rpm, and an open spacer to allow some air exchange to promote high rpm performance.
But an unported 2101 performer with an open gasket and a 4 hole combo may give similar results.
I experimented with several combo's before I settled on the one I have. All clock timing, throttle response and seat of the pants to quantify my results. So no dyno to back it up as far as which combo produced the most power. Just which combo produced the best results for what I wanted.
Edit: if I compute the CR with the Pistons .025 in the hole at TDC and a .051 gasket then I get 5 cc's for those Pistons.
This does seem more likely vs a decked block from GM. I don't see mention of it in the spec sheet though.
Did you measure how far down the Pistons were at TDC?
Last edited by REELAV8R; 04-21-2017 at 11:43 PM.
04-22-2017, 07:36 AM
#94
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Deck
The pic of the Pistons helps. Those are not what I found when I did a search for zz4 pistons.
If I put the numbers you gave and assume a zero deck? then to get a 10:1 cr the Pistons are 11 cc's (which seems big) assuming the heads they use for that computation are 58 cc's with a .051 gasket.
I would agree that the 2101 or similar performer would be restrictive, just after what rpm is the question, maybe not until 5500? I can't say.
There are trade offs for sure. RPM and higher hp or torque and lower rpm.
I ported out my 2101 to try to get the best of both worlds. I also use a 4 hole spacer for low rpm, and an open spacer to allow some air exchange to promote high rpm performance.
But an unported 2101 performer with an open gasket and a 4 hole combo may give similar results.
I experimented with several combo's before I settled on the one I have. All clock timing, throttle response and seat of the pants to quantify my results. So no dyno to back it up as far as which combo produced the most power. Just which combo produced the best results for what I wanted.
Edit: if I compute the CR with the Pistons .025 in the hole at TDC and a .051 gasket then I get 5 cc's for those Pistons.
This does seem more likely vs a decked block from GM. I don't see mention of it in the spec sheet though.
Did you measure how far down the Pistons were at TDC?
If I put the numbers you gave and assume a zero deck? then to get a 10:1 cr the Pistons are 11 cc's (which seems big) assuming the heads they use for that computation are 58 cc's with a .051 gasket.
I would agree that the 2101 or similar performer would be restrictive, just after what rpm is the question, maybe not until 5500? I can't say.
There are trade offs for sure. RPM and higher hp or torque and lower rpm.
I ported out my 2101 to try to get the best of both worlds. I also use a 4 hole spacer for low rpm, and an open spacer to allow some air exchange to promote high rpm performance.
But an unported 2101 performer with an open gasket and a 4 hole combo may give similar results.
I experimented with several combo's before I settled on the one I have. All clock timing, throttle response and seat of the pants to quantify my results. So no dyno to back it up as far as which combo produced the most power. Just which combo produced the best results for what I wanted.
Edit: if I compute the CR with the Pistons .025 in the hole at TDC and a .051 gasket then I get 5 cc's for those Pistons.
This does seem more likely vs a decked block from GM. I don't see mention of it in the spec sheet though.
Did you measure how far down the Pistons were at TDC?
As for the 2101, it may have some merit. Thanks for your input.
04-22-2017, 10:20 AM
#95
Drifting
Needs a Blower?
I'm not usually a max power kind of guy, but for some strange reason.
This engine screams twin screw blower!
A 9 / 1 comp and thick unbored cylinders seem strong enough.
I realize this is not cheap, but big power never is!
Sorry for the hi-jack.
R
This engine screams twin screw blower!
A 9 / 1 comp and thick unbored cylinders seem strong enough.
I realize this is not cheap, but big power never is!
Sorry for the hi-jack.
R
04-22-2017, 12:55 PM
#96
Le Mans Master
The ZZ4 block is at 9.025....not zero decked
I also did some searches last night on piston cc for these pistons, and only found a few hits that even identified it, but they all said 6 cc.
As for the 2101, it may have some merit. Thanks for your input.
This from edebrock on their web site;
PERFORMER RPM™ (1500 - 6500 RPM)
A dual-plane, high-rise designed with a 180° firing order greatly produces incredible top-end horsepower while retaining great throttle response. Their larger plenums and runners match high-lift cams, free flowing exhausts and other modifications of a high-output engine. Great for street or strip.
A dual-plane, high-rise designed with a 180° firing order greatly produces incredible top-end horsepower while retaining great throttle response. Their larger plenums and runners match high-lift cams, free flowing exhausts and other modifications of a high-output engine. Great for street or strip.
Of course they also say the 7104 will not fit under the Corvette hood. You got it to work, sooo....
If they do employ larger plenum and larger runners this will slow down the charge initially out of the carb vs a smaller runner dimension and less plenum volume. This could cause some loss of torque below peak torque. Speeding it up a bit couldn't hurt.
Too small and you loose some top end. Too little plenum volume can be manipulated by using an open spacer vs a 4 hole.
Just one more thing and I'll shut up.
Cooling or keeping cool the intake charge is a bonus for torque.
The performer intake (2101), and I see the 7104 does too, has 4 runners directly exposed to the the hot oil mist in the lifter valley. An oil shield of some description will help keep the oil from heating up the bottom runners and the intake charge to those cylinders. Also blocking off the crossover heat channel is a plus for removing unwanted heat.
I am also a believer in cold air intake. Cooler air is denser and will pull more fuel (to a limited degree)and create more cylinder pressure. I don't know if you're using CAI of any sort or not.
Of course more displacement is definitely a cure for the lack of torque on the 350.
05-28-2017, 04:46 PM
#97
Instructor
Sorry I missed this one. If you looking for BBC torque then I would do the following:
4.125 x 3.75 x 5.7 Rod
Shoot for a compression
Reuse your 180cc heads (Keep in mind biggest factory head was 153cc)
Airgap intake with a 750HP Holley
1.6 Rockers
The cam I do for these heads, 560/540 233/235 on a 108
You would do better with a set of 1 3/4" headers
This combo will make more torque then HP as it will peak around 5800 rpm but the seat of pants feel will give you that BBC "sit in the seat, shut up and hold on"!
4.125 x 3.75 x 5.7 Rod
Shoot for a compression
Reuse your 180cc heads (Keep in mind biggest factory head was 153cc)
Airgap intake with a 750HP Holley
1.6 Rockers
The cam I do for these heads, 560/540 233/235 on a 108
You would do better with a set of 1 3/4" headers
This combo will make more torque then HP as it will peak around 5800 rpm but the seat of pants feel will give you that BBC "sit in the seat, shut up and hold on"!
I would like this set up in my 70 LT-1 vert with a 406 ci short block w/Edel. RPM heads and flat top pistons . I just noticed you custom grind and sell these cam's . Could you pm me with a price for one in a hyd flat tappet? Thank you .
Last edited by zebebad; 05-28-2017 at 05:04 PM.
05-29-2017, 10:46 AM
#98
Instructor
406 dart shp in a 77
went with a 406 sb, fully forged ($500 xtra compared to 9000 crank and lesser rods) howards roller cam at 1500 to 6500 with choppy idle has great vacuum,matching beehive springs from howards, 215cc dart pro1 heads, 750 carter(edelbrock carb, same thing) 1 5/8 headers(was not going to spend for 1 3/4" and change my exhaust) stayed with performer intake due to $300 for air gap to make 20 hp (intake comparison chart showing intakes and what change they make)
700r4 with 308 rear
car just walks away from everything, bottom and top
street car 1500 rpm at 65 mph cruise
5 speed would be a better trans, maybe later, 355, 373 rear would be better,
whats that, another $3000 and alot of work
700r4 with 308 rear
car just walks away from everything, bottom and top
street car 1500 rpm at 65 mph cruise
5 speed would be a better trans, maybe later, 355, 373 rear would be better,
whats that, another $3000 and alot of work
