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How about this Comp Cam HR Extreme Energy grind. XR264HR
Almost exactly what I was thinking about. The advertised duration is about 10 degrees shorter than some of the other HRs, with the same .050 spec, and this helps low end tq
.
HYDRAULIC ROLLER − Mild performance applications,
very good mid-range, 3.23-3.73 gears. Hyd. Hyd. 1200 to 5200 12-412-810,46 XR264HR 264 270 212 218 .487 .495 110°
How about this Comp Cam HR Extreme Energy grind. XR264HR
Almost exactly what I was thinking about. The advertised duration is about 10 degrees shorter than some of the other HRs, with the same .050 spec, and this helps low end tq
.
HYDRAULIC ROLLER − Mild performance applications,
very good mid-range, 3.23-3.73 gears. Hyd. Hyd. 1200 to 5200 12-412-810,46 XR264HR 264 270 212 218 .487 .495 110°
The above blue print motor has a very mild cam for 427 ci and big 220cc heads. My first 427 had a comp extreme 242/248 roller and I thought that it was a little disappointing. 180 cc heads and wimpy cam would be disasterous. The rule is the bigger the port flow CFM the less duration required to make the same HP. You need all the lift you can to be flowing the highest CFM to fill longer stroke engines. That is why I have .685/714 lift in my motor with 252/256 @ .050 227cc heads
It looks like if you want to build a low rpm torque motor you guys are looking at race car parts...roller cam, aftermarket blocks with long rods, etc...…
The OP asked for a strong low rpm, 5000 rpm motor. Go steal a tow truck and pull the motor! Why waste so much money on high end parts he's never going to actually need. A 9:1 cr 400 with a 214 degree flat tappet cam will pull the foundation out from under a barn,....and cost next to nothing to build.
I just looked at the Pace 427 price tag......OMG!!!!
Last edited by The Money Pit; Nov 7, 2019 at 08:51 PM.
It looks like if you want to build a low rpm torque motor you guys are looking a race car parts...roller cam, aftermarket blocks with long rods, etc...…
The OP asked for a strong low rpm, 5000 rpm motor. Go steal a tow truck and pull the motor! Why waste so much money on high end parts he's never going to actually need. A 9:1 cr 400 with a 214 degree flat tappet cam will pull the foundation out from under a barn,....and cost next to nothing to build.
Did anyone here actually listen to what the OP wants?
He was very specific, he does not want a high rpm high hp motor.
He wants a under 5000 rpm stump puller, with as many cubes as he can get from a SBC, and he already has AFR 180 heads and said he will be using a Dart SHP block and a hydraulic cam.
Give him advice that works with that.
Can he do better than 417 cubes, easiiy? Is it worth it to do so?
It looks like if you want to build a low rpm torque motor you guys are looking at race car parts...roller cam, aftermarket blocks with long rods, etc...…
The OP asked for a strong low rpm, 5000 rpm motor. Go steal a tow truck and pull the motor! Why waste so much money on high end parts he's never going to actually need. A 9:1 cr 400 with a 214 degree flat tappet cam will pull the foundation out from under a barn,....and cost next to nothing to build.
I just looked at the Pace 427 price tag......OMG!!!!
That price is 8k to 12k cheaper than a custom built SBC 427. I build 6 to 8 of them a year. All in the 15k to 20k price range.
I just looked at your current 350.
Roughly 325 ftlbs at 1000 rpm.
Pretty soft tq at low end with that combo but feels strong upstairs at 2500 up.to 6000
The one step milder cam I mentioned is worth 25ftlb down low. even on the 350.
The 3.8-4.0" stroke is worth 50 ftlbs down low.
The 4.125" bore is worth another 25 ftlbs down low.
Goes up to 425 tq at 1000 rpm.
HP doesn't really change much from where you are now, it just happens 1000 rpm lower.
Resulting curve looks almost exactly like a BBC 427 390HP.
current 350:
Last edited by leigh1322; Nov 7, 2019 at 10:26 PM.
My 2 cents worth and real opinion. I think in a standard deck height block a 406 is the right engine size. 3.75 stroke with 6.00 stroker clearanced rods would allow you to keep a full sized base circle cam, have pistons with some form of a decent compression height and no oil ring supports. It would be such a huge improvement to what you have now and not side load the rings and piston skirts as much as the 4.00 stroke. A better long term engine build. To me I would never build a 427 or bigger if I could not use a 9.325 deck height dart iron eagle block then you could use some longer rods not have very low rod ratio, sure you can do it in the regular block. But any pro engine builder if you ask them will tell you ideally a 1.75 rod to stroke ratio is best anything else a compromise just to make it work. That also sort of matches the original sbc design when it had a 3.00 stroke 5.7 rod it had a 1.72 rod ratio if I remember right. Notice how when the ls engine first came out they went to a 9.20 deck height and used a 6.125 rod even though there new 350 only had a 3.650 stroke crank, 3.90 bore.
Last edited by Little Mouse; Nov 8, 2019 at 12:50 AM.
The two graphs you posted tell the story pretty accurately, and show the fix I am looking for. I appreciate your efforts and posts. What would really be cool is seeing both curves on the same graph. What computer program are you using?
As usual, people begin to post comments that increasingly move the engine back to the high RPM engine I do not want. Happens every time. I think that guys who race cars, or build high RPM motors, simply do not consider a lower end torque a real engine. Some of them strongly believe their high RPM engine is what I need to meet my requirements. And one disadvantage I have is that I have never driven a strong low end torque engine. My 350 gets close to what I want, but only when I floor it. I read all the time about guys with LS5 early Corvettes about how the torque pushes you back in the seat down low, and it sounds fun to me. Speed is not my goal, as I drive on city streets, and curvy Pennsylvania roads. My wife's 4 cylinder Toyota Camry will go 90 mph,......if you wind it out, so what? My 2015 F150 with 5.0 V8 will go fast......if I floor it, so what? I think you understand my goal, and I appreciate your input.
Last edited by Shovels and Vettes; Nov 8, 2019 at 07:02 AM.
My 2 cents worth and real opinion. I think in a standard deck height block a 406 is the right engine size. 3.75 stroke with 6.00 stroker clearanced rods would allow you to keep a full sized base circle cam, have pistons with some form of a decent compression height and no oil ring supports. It would be such a huge improvement to what you have now and not side load the rings and piston skirts as much as the 4.00 stroke. A better long term engine build. To me I would never build a 427 or bigger if I could not use a 9.325 deck height dart iron eagle block then you could use some longer rods not have very low rod ratio, sure you can do it in the regular block. But any pro engine builder if you ask them will tell you ideally a 1.75 rod to stroke ratio is best anything else a compromise just to make it work. That also sort of matches the original sbc design when it had a 3.00 stroke 5.7 rod it had a 1.72 rod ratio if I remember right. Notice how when the ls engine first came out they went to a 9.20 deck height and used a 6.125 rod even though there new 350 only had a 3.650 stroke crank, 3.90 bore.
Little Mouse,
I agree with what you said above, and feel much more comfortable with a 406. I started out with the idea of a 406, and got talked into bigger by Skip White, based on the idea that for a small?? amount more money, you can have so much more. But my problem with it is that I think its pushing too many limits of the design, exactly as you posted. Sure, it can all be done with enough grinding and compromise, all for the sake of building a race car engine. In another life, or another situation, I should have bought a LS5 early 70's Corvette, but I could not afford it at the time, nor do I have any desire to sell mine now. I drive this car as much as I can outside of winter, with the limit being my insurance company limits of 6000 miles per year, and I want it to last for years to come. This is not some weekend race car or car show parking lot car. And I don't care about bragging rights, do not street race, or do I have ego problems. Many Corvette owners drive the cars to and from car shows, and spend most of their time in garages. And the biggest thing is, that I have no interest in driving faster than 70 mph, anywhere, anytime. Its not me. The race boys make fun of me, and I just smile. I do like accelerating, and with the performance mods done on the suspension and steering, I enjoy the twisty roads of PA in a sporty way. I want the engine to be there in the turns. Maybe its the difference between drag racing and road course racing.
I am still pondering this, but I am leaning toward 406. The AFR 180 heads clearly are more appropriate than on bigger engines. The 3.75 stroke fits into the block with a standard base cam, which is a plus, and the compression height is better. I can spend the extra money I save on possibly a better carb although my Lars built Quadrajet runs great. I might consider 1.6 roller rockers to replace my 1.52 Comp Pro Magnums, but again, it may be pushing the limits of my AFR 180 springs (max lift .600) and 3/8 rocker studs......all for a small gain and more money. Its all theory based on reading for me, so it becomes difficult to know what is right. You certainly cannot believe everything you read.
I think building a 383 is cheaper, but not enough of a gain. A Dart SHP block is a solid foundation for a 406, with AFR 180 heads, factory GM hydraulic roller system, and all the good components I have or will buy, will make a solid and reliable, and strong enough engine for me. I hope so, cause there will be no "third try".
Skip White sells a 406 short block for $2895, with Dart SHP block, Scat cast crank, Scat rods (Pro Comp), Wiseco pistons. He agreed to install my AFR 180 heads, build the engine and dyno it. I don't have final price yet, but I suspect it will be $5000-$6000. I don't see any other companies approaching that price for the same thing. I could just buy the assembled short block from him for under $3500 including shipping, but I really would like to break it in on the dyno and make sure its good before installing it.
Last edited by Shovels and Vettes; Nov 8, 2019 at 06:55 AM.
It looks like if you want to build a low rpm torque motor you guys are looking at race car parts...roller cam, aftermarket blocks with long rods, etc...…
The OP asked for a strong low rpm, 5000 rpm motor. Go steal a tow truck and pull the motor! Why waste so much money on high end parts he's never going to actually need. A 9:1 cr 400 with a 214 degree flat tappet cam will pull the foundation out from under a barn,....and cost next to nothing to build.
I just looked at the Pace 427 price tag......OMG!!!!
Welcome to my world! And you are correct. That Pace 427 is a Blueprint manufactured engine with all the important parts their own manufactured parts. Might be just fine, but the price is too high for me, especially given its all unknown quality parts, as opposed to the Scat, Wiseco, Comp, and AFR parts I intend to use.
I built a 415 that I use in a track vehicle. Dart SHP Block - Scat Crank & Rods - AFR 210 heads and a nice smallish hydraulic roller cam. Nothing crazy. A touch over 10:1 - runs on pump premium ... Makes 500 HP & 500 ft lb.
I went with the 415 because I was going to be using this thing in the upper half of the rev range a lot (I run a MSD box with a 6,100 RPM "pill" that starts cutting spark at about 5,950), and was a bit leery about the 4.00 stroke.
You might want to check out CNC Motorsports Short Blocks...
First, quit listening to the snake-oil salesman Skip White. Do a few forum searches here and on other sites like Chevelles.com and you'll see why I say that. There are a ton of better engine builders that will give honest advice.
First, quit listening to the snake-oil salesman Skip White. Do a few forum searches here and on other sites like Chevelles.com and you'll see why I say that. There are a ton of better engine builders that will give honest advice.
I do have concerns about Skip White, simply because his prices are so much lower than everyone else. That typically means something.
first, quit listening to the snake-oil salesman skip white. Do a few forum searches here and on other sites like chevelles.com and you'll see why i say that. There are a ton of better engine builders that will give honest advice.
I agree with what you said above, and feel much more comfortable with a 406. I started out with the idea of a 406, and got talked into bigger by Skip White, based on the idea that for a small?? amount more money, you can have so much more. But my problem with it is that I think its pushing too many limits of the design, exactly as you posted. Sure, it can all be done with enough grinding and compromise, all for the sake of building a race car engine. In another life, or another situation, I should have bought a LS5 early 70's Corvette, but I could not afford it at the time, nor do I have any desire to sell mine now. I drive this car as much as I can outside of winter, with the limit being my insurance company limits of 6000 miles per year, and I want it to last for years to come. This is not some weekend race car or car show parking lot car. And I don't care about bragging rights, do not street race, or do I have ego problems. Many Corvette owners drive the cars to and from car shows, and spend most of their time in garages. And the biggest thing is, that I have no interest in driving faster than 70 mph, anywhere, anytime. Its not me. The race boys make fun of me, and I just smile. I do like accelerating, and with the performance mods done on the suspension and steering, I enjoy the twisty roads of PA in a sporty way. I want the engine to be there in the turns. Maybe its the difference between drag racing and road course racing.
I am still pondering this, but I am leaning toward 406. The AFR 180 heads clearly are more appropriate than on bigger engines. The 3.75 stroke fits into the block with a standard base cam, which is a plus, and the compression height is better. I can spend the extra money I save on possibly a better carb although my Lars built Quadrajet runs great. I might consider 1.6 roller rockers to replace my 1.52 Comp Pro Magnums, but again, it may be pushing the limits of my AFR 180 springs (max lift .600) and 3/8 rocker studs......all for a small gain and more money. Its all theory based on reading for me, so it becomes difficult to know what is right. You certainly cannot believe everything you read.
I think building a 383 is cheaper, but not enough of a gain. A Dart SHP block is a solid foundation for a 406, with AFR 180 heads, factory GM hydraulic roller system, and all the good components I have or will buy, will make a solid and reliable, and strong enough engine for me. I hope so, cause there will be no "third try".
Skip White sells a 406 short block for $2895, with Dart SHP block, Scat cast crank, Scat rods (Pro Comp), Wiseco pistons. He agreed to install my AFR 180 heads, build the engine and dyno it. I don't have final price yet, but I suspect it will be $5000-$6000. I don't see any other companies approaching that price for the same thing. I could just buy the assembled short block from him for under $3500 including shipping, but I really would like to break it in on the dyno and make sure its good before installing it.
I do not know there prices but dart does make assembled short blocks you just pick the parts you want used, I think that would be a good solution to trying to find a good engine builder.
To my knowledge I don't recall at least in the past any car manufacture ever using a compression height piston so short it had oil ring supports. In higher rpm builds it's good to keep piston weight down your not doing that. There is almost never a free lunch everything you do can have tradeoffs. To me the 750 QJ you have is perfect
for what you want to do.
