Advanced Induction PR 243's & HR on LS1 - 600hp+
10-11-2011, 01:35 PM
#1
Advanced Induction PR 243's & HR on LS1 - 600hp+ Gents,
I don't get to post as often as I'd like, but this is a build that is a bit of a departure from the norm. Though a bit off the common path, it should get the gears turning for the budget minded guys. The engine is an overbore LS1 rebuild set up to run in a class that allows no head or manifold porting of any kind. We can only valve job the head, prepare valves, mill heads, and swap springs etc. so it is the perfect candidate for our $495 Performance Rebuild head work. Combined with an appropriate HR cam, it makes for a great combo despite the less than optimal manifold we are forced to run.
Specs:
352.X cid
12:1
Ai Performance Rebuild 243's - stock valve sizes
Edelbrock SVictor/750 carb
Hydraulic Roller lifters (functional) & .540" lift (.550" max allowable) HR cam
ARH 1-3/4" stepped LT headers
It managed 625hp this first test session.
Being pressed for time, there was only time to put a few pulls on it at this point. The table below is an average of the last two dyno pulls:
Hopefully we'll be able to get it back on the engine dyno to try the usual tweaks to determine precisely what the engine needs to run optimally. With some time spent on timing curve, oil (it was tested w/ heavy break in oil), and perhaps a manifold change it will likely creep upwards appreciably. Presently the core shift in the manifold & head stack up to produce a terrible mating condition. With some time spent mocking up multiple sets of heads & manifolds we can likely come across some that will work better together. However, it will never be ideal since the manifold exit will always be larger than the entrance of the head port.
Feel free to ask any questions & I'll answer what I can when I'm able to. Hope you guys like it!
-Phil
I don't get to post as often as I'd like, but this is a build that is a bit of a departure from the norm. Though a bit off the common path, it should get the gears turning for the budget minded guys. The engine is an overbore LS1 rebuild set up to run in a class that allows no head or manifold porting of any kind. We can only valve job the head, prepare valves, mill heads, and swap springs etc. so it is the perfect candidate for our $495 Performance Rebuild head work. Combined with an appropriate HR cam, it makes for a great combo despite the less than optimal manifold we are forced to run.
Specs:
352.X cid
12:1
Ai Performance Rebuild 243's - stock valve sizes
Edelbrock SVictor/750 carb
Hydraulic Roller lifters (functional) & .540" lift (.550" max allowable) HR cam
ARH 1-3/4" stepped LT headers
It managed 625hp this first test session.
Being pressed for time, there was only time to put a few pulls on it at this point. The table below is an average of the last two dyno pulls:
Hopefully we'll be able to get it back on the engine dyno to try the usual tweaks to determine precisely what the engine needs to run optimally. With some time spent on timing curve, oil (it was tested w/ heavy break in oil), and perhaps a manifold change it will likely creep upwards appreciably. Presently the core shift in the manifold & head stack up to produce a terrible mating condition. With some time spent mocking up multiple sets of heads & manifolds we can likely come across some that will work better together. However, it will never be ideal since the manifold exit will always be larger than the entrance of the head port.
Feel free to ask any questions & I'll answer what I can when I'm able to. Hope you guys like it!
-Phil
10-11-2011, 06:31 PM
#4
how did you overbore an ls1 to 352 ci? what is the bore on that?
I have a 64 chevy II Nova that is drag only, I have to rebuild the bottom end and am thinking about taking the truck intake off and going with a Super victor intake and carb. with the msd 6010 box instead of fuel injected with stock computer.
It seems that with a drag only setup , it would allow me to spin the little engine a bit higher .
I have a 64 chevy II Nova that is drag only, I have to rebuild the bottom end and am thinking about taking the truck intake off and going with a Super victor intake and carb. with the msd 6010 box instead of fuel injected with stock computer.
It seems that with a drag only setup , it would allow me to spin the little engine a bit higher .
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10-16-2011, 12:24 PM
#9
Thanks for the kind words, guys!
It is ~.037" over - 3.935"
If you have a GM LS1 short block I'd stick with the typical 3.905 etc. pistons. There isn't much to be gained from another .015" radially & a few inches.
Thanks Zach! I think Rick may try and haul it over to you guys to race the dyno out of curiosity at some point.
The cam size would be roughly comparable to something like a 24X/24X XER lobed comp grind. It has much lower pos/neg accels than typical HR lobes since the class won't allow blocked or bottomed out lifters & needs ~8krpm to be competitive.
It is always entertaining to see how much you can make with the bare minimum work. Often guys cheat up heads/manifolds for classes like this, but since this was our first round down range it seemed smartest to be well to the safe side. There is zero hand work/blending involved, and the CNC'd valve job actually is the same one I cut for the $495 Performance Rebuild option.
Glad you guys like it!
-Phil
how did you overbore an ls1 to 352 ci? what is the bore on that?
I have a 64 chevy II Nova that is drag only, I have to rebuild the bottom end and am thinking about taking the truck intake off and going with a Super victor intake and carb. with the msd 6010 box instead of fuel injected with stock computer.
It seems that with a drag only setup , it would allow me to spin the little engine a bit higher .
I have a 64 chevy II Nova that is drag only, I have to rebuild the bottom end and am thinking about taking the truck intake off and going with a Super victor intake and carb. with the msd 6010 box instead of fuel injected with stock computer.
It seems that with a drag only setup , it would allow me to spin the little engine a bit higher .
If you have a GM LS1 short block I'd stick with the typical 3.905 etc. pistons. There isn't much to be gained from another .015" radially & a few inches.
The cam size would be roughly comparable to something like a 24X/24X XER lobed comp grind. It has much lower pos/neg accels than typical HR lobes since the class won't allow blocked or bottomed out lifters & needs ~8krpm to be competitive.
Glad you guys like it!
-Phil
10-16-2011, 06:28 PM
#10
Just one more reason I'm glad I'm choosing AI for my work. Can't wait to get this going!!
By the way Phil, I'm the guy that's been emailing you a ton lately about my 243/799 sell/keep/241 valve options, etc for my 66 Nova. I appreciate the time you've taken with me so far, and that's the #1 reason I'm going with you guys. Your proven performance is a very close 2nd.
By the way Phil, I'm the guy that's been emailing you a ton lately about my 243/799 sell/keep/241 valve options, etc for my 66 Nova. I appreciate the time you've taken with me so far, and that's the #1 reason I'm going with you guys. Your proven performance is a very close 2nd.
10-22-2011, 06:06 PM
#11
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Thanks for the kind words, guys!
It is ~.037" over - 3.935"
If you have a GM LS1 short block I'd stick with the typical 3.905 etc. pistons. There isn't much to be gained from another .015" radially & a few inches.
Thanks Zach! I think Rick may try and haul it over to you guys to race the dyno out of curiosity at some point.
The cam size would be roughly comparable to something like a 24X/24X XER lobed comp grind. It has much lower pos/neg accels than typical HR lobes since the class won't allow blocked or bottomed out lifters & needs ~8krpm to be competitive.
It is always entertaining to see how much you can make with the bare minimum work. Often guys cheat up heads/manifolds for classes like this, but since this was our first round down range it seemed smartest to be well to the safe side. There is zero hand work/blending involved, and the CNC'd valve job actually is the same one I cut for the $495 Performance Rebuild option.
Glad you guys like it!
-Phil
It is ~.037" over - 3.935"
If you have a GM LS1 short block I'd stick with the typical 3.905 etc. pistons. There isn't much to be gained from another .015" radially & a few inches.
Thanks Zach! I think Rick may try and haul it over to you guys to race the dyno out of curiosity at some point.
The cam size would be roughly comparable to something like a 24X/24X XER lobed comp grind. It has much lower pos/neg accels than typical HR lobes since the class won't allow blocked or bottomed out lifters & needs ~8krpm to be competitive.
It is always entertaining to see how much you can make with the bare minimum work. Often guys cheat up heads/manifolds for classes like this, but since this was our first round down range it seemed smartest to be well to the safe side. There is zero hand work/blending involved, and the CNC'd valve job actually is the same one I cut for the $495 Performance Rebuild option.
Glad you guys like it!
-Phil
Rob
