Thinking about a 402 LS2
Thread Starter
Racer
Joined: Mar 2004
Posts: 291
Likes: 0
From: Pulaski TN
Thinking about a 402 LS2
The main reason I'm going 402 is to get the increased stroke to give me more torque no matter what rpm it is. I want a torque monster, but don't want it falling off at the top end. Anyway, ...
My goals are
Reliability, I want this thing to last just as long as a stock 400hp LS2 would, if not longer.
500rwhp at least, I guess that would be 550 to 575 crank hp
500 crank torque at least. I'd like 500rwtq, but have noticed that usually the torque on LS engines is lower than the hp number.
Ok, so, do you think I can make it with what I have planed.
4" Crank. Forged bottom end. Crank, rods, pistons.
Cam somewhere around 225/230 to 230/235 with .575-.600 lift with a 114 lsa, Not to crazy of a cam because I do drive this on the street a Lot.
CNC ported LS2 243 heads.
LG Long Tube headers with LG high flow cats.
Corsa 3" exhaust.
K&N cone filter, just trying to think of anything that effects power.
Tune obviously, not sure you could change that much without a tune.
Thanks,
Steven
My goals are
Reliability, I want this thing to last just as long as a stock 400hp LS2 would, if not longer.
500rwhp at least, I guess that would be 550 to 575 crank hp
500 crank torque at least. I'd like 500rwtq, but have noticed that usually the torque on LS engines is lower than the hp number.
Ok, so, do you think I can make it with what I have planed.
4" Crank. Forged bottom end. Crank, rods, pistons.
Cam somewhere around 225/230 to 230/235 with .575-.600 lift with a 114 lsa, Not to crazy of a cam because I do drive this on the street a Lot.
CNC ported LS2 243 heads.
LG Long Tube headers with LG high flow cats.
Corsa 3" exhaust.
K&N cone filter, just trying to think of anything that effects power.
Tune obviously, not sure you could change that much without a tune.
Thanks,
Steven
Last edited by SSRogers; Nov 9, 2007 at 11:35 PM.
Safety Car
Joined: Mar 2004
Posts: 4,434
Likes: 18
From: Bartlett IL
St. Jude Donor '07-'08-'09-'10-'11
I was planning on doing either a 402 or 416 this winter and like you, reliability is at the top of my list. I know that some guys get a stroker and run it for years with little issues. But when you do a search, the percentage of guys with years of reliable service out of a stroker is not overwhelming, probably less than 50% actually.
So instead I'm doing a heads/cam LS3 and dropping it in my '01 Z06. I'm keeping the bottom end stock so I never have to worry about oiling issues.
You can do a LS7 if you want even more torque, but the price difference in my book is not worth the extra cubes.
Good luck with your decision,
Pete
So instead I'm doing a heads/cam LS3 and dropping it in my '01 Z06. I'm keeping the bottom end stock so I never have to worry about oiling issues.
You can do a LS7 if you want even more torque, but the price difference in my book is not worth the extra cubes.
Good luck with your decision,
Pete
Melting Slicks
Joined: Jun 2004
Posts: 3,439
Likes: 6
From: Newark, DE
St. Jude Donor '06
I think the numbers you are shooting for are totally reasonable. Here's the results of my LS2-based 402 installed in a C5:
A couple of points though...
I don't think you will need such a large exhaust duration bias as you propose. The purpose of doing so is to help evacuate the cylinders during the exhaust stroke, but with LGs and a 3" exhaust all the way back, I don't think that will be a concern. Also, the AFR 225 will give you larger dyno numbers up top, but at the cost of low end torque. Since you are already prepared to shell out the bux for AFR, a better choice (given your goals) might be ported 205s.
The keys to longevity in a built motor are (IMO):
A couple of points though...
I don't think you will need such a large exhaust duration bias as you propose. The purpose of doing so is to help evacuate the cylinders during the exhaust stroke, but with LGs and a 3" exhaust all the way back, I don't think that will be a concern. Also, the AFR 225 will give you larger dyno numbers up top, but at the cost of low end torque. Since you are already prepared to shell out the bux for AFR, a better choice (given your goals) might be ported 205s.
The keys to longevity in a built motor are (IMO):
- Don't have it tuned too lean
- Don't go too radical on cam selection
- Keep up on routine maintenance (oil changes, valve springs, etc.)
Thread Starter
Racer
Joined: Mar 2004
Posts: 291
Likes: 0
From: Pulaski TN
I was planning on doing either a 402 or 416 this winter and like you, reliability is at the top of my list. I know that some guys get a stroker and run it for years with little issues. But when you do a search, the percentage of guys with years of reliable service out of a stroker is not overwhelming, probably less than 50% actually.
The most common thing I have found is oil usage, but a good builder should be able to do it right. I mean, GM's production LS7 has a 4" crank so, this should be possible.
Steven
Thread Starter
Racer
Joined: Mar 2004
Posts: 291
Likes: 0
From: Pulaski TN
A couple of points though...
I don't think you will need such a large exhaust duration bias as you propose. The purpose of doing so is to help evacuate the cylinders during the exhaust stroke, but with LGs and a 3" exhaust all the way back, I don't think that will be a concern. Also, the AFR 225 will give you larger dyno numbers up top, but at the cost of low end torque. Since you are already prepared to shell out the bux for AFR, a better choice (given your goals) might be ported 205s.
I don't think you will need such a large exhaust duration bias as you propose. The purpose of doing so is to help evacuate the cylinders during the exhaust stroke, but with LGs and a 3" exhaust all the way back, I don't think that will be a concern. Also, the AFR 225 will give you larger dyno numbers up top, but at the cost of low end torque. Since you are already prepared to shell out the bux for AFR, a better choice (given your goals) might be ported 205s.
What are the stock heads, 200? I just figured with stock intake and a 402 I might could get away with 225s.
Thanks
Oh and the reason I put the cam numbers that I did is because I was thinking about a G5X1 which is 228/232 .588/.574 112 or 114
Also, If your car is an auto then you might actually be making the crank hp that I would need to put down 500rwhp through a manual.
Last edited by SSRogers; Nov 4, 2007 at 07:29 PM.
Melting Slicks
Joined: Jun 2004
Posts: 3,439
Likes: 6
From: Newark, DE
St. Jude Donor '06
Originally Posted by SSRogers
What Cam numbers would you recomend? I want to keep my cam resonable, that's one reason for the 114 lsa instead of a 112.
* 228/232 .581/.588 114 +4
This is flowing through LG Pros w/ hi-flow cats and Corsa Touring exhaust.
If your car is an auto then you might actually be making the crank hp that I would need to put down 500rwhp through a manual.
Drifting
Joined: Nov 2002
Posts: 1,651
Likes: 125
From: laguna niguel ca
If you're going to all that cost, why not step up to an LS3 (L92) block.
It has better features than the LS2 block. ( better strength, better breathing between cylinders). Also with a 4.065 bore and a 4.100 crank it's a 427. That's what I did. The heads you mentioned will work just fine, or you can step up to the L92 heads CNC'ed and it will be even better.
It has better features than the LS2 block. ( better strength, better breathing between cylinders). Also with a 4.065 bore and a 4.100 crank it's a 427. That's what I did. The heads you mentioned will work just fine, or you can step up to the L92 heads CNC'ed and it will be even better.
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Team Owner
Joined: Jan 2006
Posts: 20,800
Likes: 59
From: Tellico Village, Tn
St. Jude Donor '08
There was an engine company at SEMA who increased the deck height on an LS2 block and made 500 c.i. Made monster torque. Indicated they had run that engine consistantly at 7500 rpm. If I had to do it over again, that would be my choice. Actually provided them to Scoggins Dickey
Burning Brakes
Joined: Mar 2006
Posts: 906
Likes: 1
From: SF Bay CA
If you're going to all that cost, why not step up to an LS3 (L92) block.
It has better features than the LS2 block. ( better strength, better breathing between cylinders). Also with a 4.065 bore and a 4.100 crank it's a 427. That's what I did. The heads you mentioned will work just fine, or you can step up to the L92 heads CNC'ed and it will be even better.
It has better features than the LS2 block. ( better strength, better breathing between cylinders). Also with a 4.065 bore and a 4.100 crank it's a 427. That's what I did. The heads you mentioned will work just fine, or you can step up to the L92 heads CNC'ed and it will be even better.
Thread Starter
Racer
Joined: Mar 2004
Posts: 291
Likes: 0
From: Pulaski TN
As tempting as a 427 is, believe it or not I am trying to keep a handle on this project so price And power doesn't run away from me. I want the power of a FI kit, but with all motor (NA). And I don't want to use nitrous oxide either because there is no way anybody can convince me that wouldn't hurt my engine. And I'm an NA guy at heart. I know that FI is where the big power is, and will turbo my track car soon after I do this, a big reason I don't want to get carried away with this one. The track car will have a ton of power. I'm just looking for good streetable power with this and think that 500rwhp no more/no less would be about right. That's about 150hp over stock, should be doable with crank, heads, cam, headers.
Drifting
Joined: Nov 2002
Posts: 1,651
Likes: 125
From: laguna niguel ca
Drifting
Joined: Nov 2002
Posts: 1,651
Likes: 125
From: laguna niguel ca
As tempting as a 427 is, believe it or not I am trying to keep a handle on this project so price And power doesn't run away from me. I want the power of a FI kit, but with all motor (NA). And I don't want to use nitrous oxide either because there is no way anybody can convince me that wouldn't hurt my engine. And I'm an NA guy at heart. I know that FI is where the big power is, and will turbo my track car soon after I do this, a big reason I don't want to get carried away with this one. The track car will have a ton of power. I'm just looking for good streetable power with this and think that 500rwhp no more/no less would be about right. That's about 150hp over stock, should be doable with crank, heads, cam, headers.
Thread Starter
Racer
Joined: Mar 2004
Posts: 291
Likes: 0
From: Pulaski TN
With a somewhat small street cam, this motor made 525rwhp/500rwtq. All motor no forced induction. Mine is a daily driver, on the street, in traffic and the highway. The cam I selected was a comp cam 232/234/595/598/112LSA's. The 112 LSA gave the motor great midrange power and torque.
Also, I'm not getting 427 when I do the math.
Last edited by SSRogers; Nov 7, 2007 at 05:27 PM.
Former Vendor
Joined: Aug 2005
Posts: 16,897
Likes: 412
From: Lewisville TX
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
The 402 makes for a nice motor build if you are looking to get some more power from the car and not get as radical with the setup as what you would a 6.0L motor, or have near the costs involved of a 427. You will see more of a gain in torque than what you will over all horsepower by doing the stroker, but that is what is going to make the car a lot more fun to drive.
We have done a few different ones and I would be more than happy to help anyway I can from a complete install to a mail order crate motor.
We have done a few different ones and I would be more than happy to help anyway I can from a complete install to a mail order crate motor.
Team Owner
Joined: Jul 2004
Posts: 24,652
Likes: 298
From: NJ
St. Jude Donor '05-'08
We are building a 402 for my road track car right now. We have had many customers happy with their street versions and when I look at the hp/tq curves I know it will be a perfect track engine.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
2 of my buddies just built 402's with all the best parts. They are beasts but neither got 500 rwtq NA. Truth is traction is now the limiting issue for them for street use so whether it's 465 tq or 500 tq feathering the throttle is the name of the game except on drag radials.
Here's Doug's original write up with lots of details:
http://forums.corvetteforum.com/show....php?t=1802758
And here's his nitrous results, he got more power NA with the tune at 515/465, on the bottle, 630/600.
http://forums.corvetteforum.com/show....php?t=1831818
If you like PM Doug, he's well versed in engine builds and is a very helpful guy.
Here's Doug's original write up with lots of details:
http://forums.corvetteforum.com/show....php?t=1802758
And here's his nitrous results, he got more power NA with the tune at 515/465, on the bottle, 630/600.
http://forums.corvetteforum.com/show....php?t=1831818
If you like PM Doug, he's well versed in engine builds and is a very helpful guy.
Racer
Joined: Jul 2007
Posts: 276
Likes: 0
From: Lynchburg VA
St. Jude Donor '11
If you're going to all that cost, why not step up to an LS3 (L92) block.
It has better features than the LS2 block. ( better strength, better breathing between cylinders). Also with a 4.065 bore and a 4.100 crank it's a 427. That's what I did. The heads you mentioned will work just fine, or you can step up to the L92 heads CNC'ed and it will be even better.
It has better features than the LS2 block. ( better strength, better breathing between cylinders). Also with a 4.065 bore and a 4.100 crank it's a 427. That's what I did. The heads you mentioned will work just fine, or you can step up to the L92 heads CNC'ed and it will be even better.
SSRogers - the LS3 block may be a good foundation. That's what my tuner was talking to me about me doing. I am thinking he was talking in the under $10K range with my current mods. It was not clear what he was planning off of my current motor. I asume not much
Thread Starter
Racer
Joined: Mar 2004
Posts: 291
Likes: 0
From: Pulaski TN
I found some 220 heads that are ported LS2 243 heads and are about 1/3 the price of the AFRs. I think the 220s might be perfect for me, because I was getting the feeling that 225s were a tad too big and didn't want to use only 205s when I believe the stock ones are 200. Found that somewhere, but not sure if it's right. Anyway, ...
What does everybody think about Livernois Motorsports?
Also, Anthony from LG,
Which of your G5 cams do you think would be right for my 402 based on what you read in this thread?
Thanks,
Steven Rogers
What does everybody think about Livernois Motorsports?
Also, Anthony from LG,
Which of your G5 cams do you think would be right for my 402 based on what you read in this thread?
Thanks,
Steven Rogers
Last edited by SSRogers; Nov 9, 2007 at 11:39 PM.
Former Vendor
Joined: Aug 2005
Posts: 16,897
Likes: 412
From: Lewisville TX
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
Depends on what all you want. We've done some real torque monsters out there with the 205 heads on them and some custom cams that are soon to be a normal item on our shelf. The G5X3 and X4 are still popular with the 402 guys. The one that we have been using lately is currently code named the G5X3 version 2.
