Input on my engine mods
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Joined: Oct 2003
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From: Clyde Ca
Input on my engine mods
I'm getting ready to place an order and thought that I would ask for some advice from the members of what I consider the best corvette forum on the web. I've got a stock 78 350 w/auto which will be a daily (after work)driver and 250 mi. weekender. Bottom and heads will be stock.
Cam: Comp cam xe268 (stock springs?)
1:5 rockers (stock push rods?)
Headers w/ duals (maybe side pipes!)
Performer intake
Holley 1850 or Q-jet ( does lars still rebuild?)
Stock Dist (lars recurve kit?)
TH350 w/shift kit (convertor stall?)
Are these mods the best upgrades for the $? I'm i forgetting anything? Any suggestions greatly appreciated.
Thanks in advance
Mark
Cam: Comp cam xe268 (stock springs?)
1:5 rockers (stock push rods?)
Headers w/ duals (maybe side pipes!)
Performer intake
Holley 1850 or Q-jet ( does lars still rebuild?)
Stock Dist (lars recurve kit?)
TH350 w/shift kit (convertor stall?)
Are these mods the best upgrades for the $? I'm i forgetting anything? Any suggestions greatly appreciated.
Thanks in advance
Mark
Le Mans Master
Joined: Apr 2001
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From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
Re: Input on my engine mods (78calvette)
I would suggest a little smaller on the cam. I know someone who put one in their car and they are disappointed at the loss of low end torque. That cam is a mid to upper rpm range cam. It will pull like help once it gets above 2000 rpm, but under that is seems like it lacks. Since you will drive the car you will probably want more low end torque. Also what is the compression ratio on the engine? A lower compression engine will not fair well with that cam.
Le Mans Master
Joined: Feb 1999
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From: Tampa Bay FL
Re: Input on my engine mods (78calvette)
I'd recommend some deeper gears and perhaps a higher stall torque converter to launch your car closer to the camshafts optimal range... also consider some mild head porting (assuming you have stock '882' heads on your '78). Do you know the size of valves on your engine (2.02 or 1.94 intake)?....
hmmm see my sig for suggestions :seeya
hmmm see my sig for suggestions :seeya
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Re: Input on my engine mods (78calvette)
I'd recommend some deeper gears and perhaps a higher stall torque converter to launch your car closer to the camshafts optimal range... also consider some mild head porting (assuming you have stock '882' heads on your '78). Do you know the size of valves on your engine (2.02 or 1.94 intake)?....
hmmm see my sig for suggestions :seeya
NOTE: Without the gear/converter change, I'd suggest using the Crane Energizer 272 Hydraulic cam. 216/216 duration, .454/.454 lift and 110 degree lobe separation. Probably the most cam you would want with a stock converter and gears.
If you are running original valve train (pushrods, springs, rockers) and intend to install a higher lift cam such as the Energizer or Xtreme Energy, I would strongly recommend refreshing your valvetrain (fresh set of stock pushrods, springs, keepers, rocker arms) to accomodate the increased 'valve action'.
[Modified by TedH, 1:35 PM 11/20/2003]
hmmm see my sig for suggestions :seeya
NOTE: Without the gear/converter change, I'd suggest using the Crane Energizer 272 Hydraulic cam. 216/216 duration, .454/.454 lift and 110 degree lobe separation. Probably the most cam you would want with a stock converter and gears.
If you are running original valve train (pushrods, springs, rockers) and intend to install a higher lift cam such as the Energizer or Xtreme Energy, I would strongly recommend refreshing your valvetrain (fresh set of stock pushrods, springs, keepers, rocker arms) to accomodate the increased 'valve action'.
[Modified by TedH, 1:35 PM 11/20/2003]
Thread Starter
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Joined: Oct 2003
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From: Clyde Ca
Re: Input on my engine mods (TedH)
Ted, Thanks for the input. I will be "refreshing" the valve train as you suggest. The valves are stock. I cannot afford the gear change at this time.
This forum has helped me a lot THANKS to all who are here.
:cheers:
Mark
This forum has helped me a lot THANKS to all who are here.
:cheers:
Mark
Safety Car
Joined: Aug 2001
Posts: 3,681
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From: Waterford Mi
Re: Input on my engine mods (78calvette)
If you want to see improvement in your engine then look for a cam that will give you the best low end torque and don't let HP numbers scare you away from it. A high lift cam needs to have a lot better heads then what your engine has to do any good. The engine has to work with your drive train fo it to have performance gains.
Thread Starter
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Joined: Oct 2003
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From: Clyde Ca
Re: Input on my engine mods (redwingvette)
redwingvette, I'm not looking for 300+ HP but something better than what I have(180). I like some what of a "lumpy" cam and good lowend torque.
This will be my first attempt to build instead of repairing whats broke.
Thanks
Mark
This will be my first attempt to build instead of repairing whats broke.
Thanks
Mark
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Drifting
Joined: Nov 2003
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From: chicago IL
Re: Input on my engine mods (78calvette)
may i suggest a demon carb, 650 speed demon or 625 road demon depending on cam. They dont cost that much more but they have better flow and are overall a better carb. :cheers: :seeya
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Joined: Oct 2003
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From: Clyde Ca
Re: Input on my engine mods (killervette666)
Killervette666, Sorry I should have said that I already have the q-Jet and Holley. B.G. builds a nice carb but that will have to be later. Thanks
Mark
Mark
Melting Slicks
Joined: Apr 1999
Posts: 2,010
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From: Moon Twp. PA USA
Re: Input on my engine mods (78calvette)
I am running a HE268 cam (single profile) with a 4 speed and an effective rear gear ratio of 3.50. Off idle it is somewhat of a dog. Launch at 1500 or above and it is ok. Don't fall for the 'you need a Demon or big Holly' line. A well rebuilt (Lars or Carb Shop) Q-Jet will be just fine for the street as long as it is jetted correctly. The Q-Jet will flow 750-795 cfm depending upon the model. Mine is as smooth as FI, no stutters or hesitation. Check my profile for mods.
Racer
Joined: Sep 2003
Posts: 420
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From: Indianapolis IN
Re: Input on my engine mods (78calvette)
:iagree:
Maybe try the 268H instead of the xe268. I know on paper the 268H looks tame, but I had one in my 67 Camaro with 2.73 gears and a stock torque converter and it would run mid 12's in the 1/4. The main difference would be I had double hump 2.02 heads and forged pistons with higher compression and a good intake.
Maybe try the 268H instead of the xe268. I know on paper the 268H looks tame, but I had one in my 67 Camaro with 2.73 gears and a stock torque converter and it would run mid 12's in the 1/4. The main difference would be I had double hump 2.02 heads and forged pistons with higher compression and a good intake.
Le Mans Master
Joined: Apr 2001
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From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
Re: Input on my engine mods (blunsford)
My old motor had the 268H in it, and was pleased with the performance of the car. With that cam and a Performer intake my car was running 14s at the track.
Melting Slicks
Joined: Aug 2003
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From: Dayton Oh
Re: Input on my engine mods (78calvette)
Here's what I'm running on my 79 daily driver w/TH350 auto. In good weather, I drive it 60mi/day to work. I've also taken it on several long trips.
XE262 cam (performance supposedly similiar to 268grind)
Edelbrock Performer EPS intake (also available for Q-jet)
Holley Street Avenger 670CFM (tuned Q-jet probably just as good or better)
2400 stall converter (really not needed with the XE262 but improves fun factor).
MidAmerica chambered exhaust
Although I also went with Dart IE heads, I'm guessing even with your stock heads, you'll see 300+HP and still have decent gas mileage. With this setup, you'll not have any vacuum or accessory problems either. Let us know what you finally decide. :cheers:
XE262 cam (performance supposedly similiar to 268grind)
Edelbrock Performer EPS intake (also available for Q-jet)
Holley Street Avenger 670CFM (tuned Q-jet probably just as good or better)
2400 stall converter (really not needed with the XE262 but improves fun factor).
MidAmerica chambered exhaust
Although I also went with Dart IE heads, I'm guessing even with your stock heads, you'll see 300+HP and still have decent gas mileage. With this setup, you'll not have any vacuum or accessory problems either. Let us know what you finally decide. :cheers:
Melting Slicks
Joined: Jun 2002
Posts: 2,842
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From: Orrtanna Pa.
Re: Input on my engine mods (marshrat99)
I also ran the Comp 268H in my 355 with stock heads and a 3.70 rear.Not a bad combo,but if you're running the stock 3.08 rear I would go with a tamer cam like the Edelbrock Performer.I've used that one too and off idle to 5500 it smokes!(This was in a 350 with stock heads and headers with duals.)
Le Mans Master
Joined: Aug 2000
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From: Brazos TX
Cruise-In IV Veteran
Cruise-In V Veteran
Re: Input on my engine mods (78calvette)
What you are proposing sounds fine to me. I would make sure you get the springs that are recommended by comp cams for whatever cam you get. Also, when you rebuild the heads have them machine the valve guides a little or check the guide to retainer clearance to be sure you have the room the run that cam. I have experience with both 268H and the ex268. They are both great cams but the ex268 is much better. There really isn't a reason for choosing the 268H when the ex268 is available. The ex268 has plenty of low end. Sure, it won't blow off the tires off idle but who really needs that. You want it to pull strong in the low to mid range and it does that just fine.
Drifting
Joined: Feb 2000
Posts: 1,607
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From: Clarksville,Tn,USA TN
Re: Input on my engine mods (burners)
I guess is really depends on what you want....My goal for my daily driver was to be able to smoke the tires at will and cruise at a low RPM on the interstate.
I did a frame off resto but for other reasons...
I built a 355 ci but it really was not what I wanted...Never had a stroked motor so I built one....I figured it would give me the down low torque that I craved for so my 388ci was born. I went with the comp 268H cam and for the little bit of running around in it that I have done, I am sure I am going to be happy.. :yesnod:
Neil in Tenn
I did a frame off resto but for other reasons...
I built a 355 ci but it really was not what I wanted...Never had a stroked motor so I built one....I figured it would give me the down low torque that I craved for so my 388ci was born. I went with the comp 268H cam and for the little bit of running around in it that I have done, I am sure I am going to be happy.. :yesnod:
Neil in Tenn