LS2 Builds
Thread Starter
Teching In
Joined: Oct 2019
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From: Currently, Flint/Detroit.
LS2 Builds Hey everyone,
I want to see everyone's LS2 builds! I have an 06 GTO and would like to see what others are doing to their LS2s!
also a little side question: Do the L92 heads flow better than the cathedral heads?
Let me know!
I want to see everyone's LS2 builds! I have an 06 GTO and would like to see what others are doing to their LS2s!
also a little side question: Do the L92 heads flow better than the cathedral heads?
Let me know!
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From: Central Cal.
L92 and LS3 heads are closely related, so yeah, they flow better than any stock cathedral head.
Thread Starter
Teching In
Joined: Oct 2019
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From: Currently, Flint/Detroit.
I have read a lot of articles about them flowing better, but I have seen a good amount of threads saying that ported cathedrals flow just as well or better than the rectangle port heads so I am kinda in a conundrum while I think about it.
Stock ls3 intake is also very good whereas cathedral engines really need a fast intake which adds a lot more cost.
It depends on your goals and budget. You’ll need a pretty rowdy ls2 build to take advantage of ls3 heads otherwise you’ll wind up with kind of a dud.
Are you building the bottom end or leaving it stock?
It depends on your goals and budget. You’ll need a pretty rowdy ls2 build to take advantage of ls3 heads otherwise you’ll wind up with kind of a dud.
Are you building the bottom end or leaving it stock?
Thread Starter
Teching In
Joined: Oct 2019
Posts: 6
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From: Currently, Flint/Detroit.
Stock ls3 intake is also very good whereas cathedral engines really need a fast intake which adds a lot more cost.
It depends on your goals and budget. You’ll need a pretty rowdy ls2 build to take advantage of ls3 heads otherwise you’ll wind up with kind of a dud.
Are you building the bottom end or leaving it stock?
It depends on your goals and budget. You’ll need a pretty rowdy ls2 build to take advantage of ls3 heads otherwise you’ll wind up with kind of a dud.
Are you building the bottom end or leaving it stock?
LS2 is on the small end of bore size for the ls3 and would benefit from being honed. Also with a bigger cam you need some compression, but milling the ls3 head down you run out of PTV clearance quick requiring valve pockets in the pistons, or fly cutting which you might not want to do.
You can get pretty far with cathedral stuff sending the 243 heads out for porting, get a dorman ls6 or fast intake and maybe port on it, get a bigger TB, and go SD or put a bigger maf sensor. Cam size is up to you.
You could also consider laying out a little extra dough at the beginning and building up exactly the motor you want on the side and then sell your ls2 when you swap it out. The money you get from the ls2 more than covers the cost of a block. Could get a sleeved 427 short block from Texas Speed for about $3k and be miles ahead of anything you can do with the ls2. Keeps your car running during the build too and then just a quick swap out and you’re back up and running.
You can get pretty far with cathedral stuff sending the 243 heads out for porting, get a dorman ls6 or fast intake and maybe port on it, get a bigger TB, and go SD or put a bigger maf sensor. Cam size is up to you.
You could also consider laying out a little extra dough at the beginning and building up exactly the motor you want on the side and then sell your ls2 when you swap it out. The money you get from the ls2 more than covers the cost of a block. Could get a sleeved 427 short block from Texas Speed for about $3k and be miles ahead of anything you can do with the ls2. Keeps your car running during the build too and then just a quick swap out and you’re back up and running.
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Nathan, after seeing this thread I had to respond to help prevent you making the same mistake I did.
I was asking this same question about 10 years ago and I made the wrong choice.
With the LS2 engine and 4.0 bore do not go for the LS3/L92 head setup. The heads do flow more CFM wise and have the potential to make more power but there is more to it.
Let me tell you why.
The LS3 head has a much larger port 210cc vs 260cc.
Going to a much larger port you will notice that your low and mid range power band will be a lot lazier and your part throttle performance will be downgraded.
Top end performance will be ok but it won't hit as hard.
LS3 heads need a minimum 4.065 bore of the LS3 to work efficiently. This is the minimum requirement to unshroud those big valves.
They do fit on 4 inch bores but it does not mean they work optimum.
For a street driven LS2 that you want to be fun the best options are the following.
Do a CNC port job on the stock heads. I recommend the TEA stage 2 package. These guys do an excellent job.
https://www.totalengineairflow.com/p...s2ls6-stage-2/
If you want aftermarket cathedrals go for the AFR 215cc head which is designed for the 4 inch bore.
https://www.airflowresearch.com/215c...cylinder-head/
These have flow numbers almost the same as a stock LS3 head but through a much smaller runner which means it is more efficient and has higher airspeed.
This is what translates into better throttle response, acceleration, and momentum.
Use one of those heads combined with a FAST 102mm intake and you will have a killer setup that will pull hard everywhere and be super responsive.
If only I could turn back time this is exactly what I would have done.
I was asking this same question about 10 years ago and I made the wrong choice.
With the LS2 engine and 4.0 bore do not go for the LS3/L92 head setup. The heads do flow more CFM wise and have the potential to make more power but there is more to it.
Let me tell you why.
The LS3 head has a much larger port 210cc vs 260cc.
Going to a much larger port you will notice that your low and mid range power band will be a lot lazier and your part throttle performance will be downgraded.
Top end performance will be ok but it won't hit as hard.
LS3 heads need a minimum 4.065 bore of the LS3 to work efficiently. This is the minimum requirement to unshroud those big valves.
They do fit on 4 inch bores but it does not mean they work optimum.
For a street driven LS2 that you want to be fun the best options are the following.
Do a CNC port job on the stock heads. I recommend the TEA stage 2 package. These guys do an excellent job.
https://www.totalengineairflow.com/p...s2ls6-stage-2/
If you want aftermarket cathedrals go for the AFR 215cc head which is designed for the 4 inch bore.
https://www.airflowresearch.com/215c...cylinder-head/
These have flow numbers almost the same as a stock LS3 head but through a much smaller runner which means it is more efficient and has higher airspeed.
This is what translates into better throttle response, acceleration, and momentum.
Use one of those heads combined with a FAST 102mm intake and you will have a killer setup that will pull hard everywhere and be super responsive.
If only I could turn back time this is exactly what I would have done.
Last edited by bortous; May 4, 2020 at 04:11 AM.
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Rectangular heads vs cathedral heads is always a hot topic around here. A powerful LS2 can be build with either head but the rectangle set up will likely be tricker to get exactly right as Bortous mentioned.
Key Parts
TEA's Stage 2 LS6/243/799 program would be my choice for a coat effective, reliable, excellent results stock cube LS2 build. I'd want 11.5 to compression if you have 93 octane gas. Maybe a little more. The heads are well proven.
An expert ported Fast 92 intake with a port matched WARR 92 mm TB would round out the intake side. 1 7/8 long tube headers.
Cam will depend on what you want from the car.
Key Parts
TEA's Stage 2 LS6/243/799 program would be my choice for a coat effective, reliable, excellent results stock cube LS2 build. I'd want 11.5 to compression if you have 93 octane gas. Maybe a little more. The heads are well proven.
An expert ported Fast 92 intake with a port matched WARR 92 mm TB would round out the intake side. 1 7/8 long tube headers.
Cam will depend on what you want from the car.
TECH Regular
Joined: Dec 2011
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You can see the 403" LS2 that I am building for my 1992 Corvette, the build is here
https://ls1tech.com/forums/conversio...minator-x.html
Admittedly, I might have built this different, it didn't start out to be a 403, and I did the engine work 5-6 years ago.
Look at post 16, there is shows links to dynos of 383 and 408s with ported 243s and the same cam as mine, and some results in Tuskys cookbook thread of what people have done with ported 243s in the quarter.
In my application, I am building a street car, so I am ok with possible top end HP limitations of the ported stock heads, for what they should give me in lower throttle response and mid range. 600 HP was my goal and *plenty* for a C4.
I think the guys above have covered the issues with chamber size and PTV clearance.
https://ls1tech.com/forums/conversio...minator-x.html
Admittedly, I might have built this different, it didn't start out to be a 403, and I did the engine work 5-6 years ago.
Look at post 16, there is shows links to dynos of 383 and 408s with ported 243s and the same cam as mine, and some results in Tuskys cookbook thread of what people have done with ported 243s in the quarter.
In my application, I am building a street car, so I am ok with possible top end HP limitations of the ported stock heads, for what they should give me in lower throttle response and mid range. 600 HP was my goal and *plenty* for a C4.
I think the guys above have covered the issues with chamber size and PTV clearance.
Last edited by Haggar; May 6, 2020 at 10:36 AM.
TECH Addict
Joined: Sep 2010
Posts: 2,898
Likes: 467
Rectangular heads vs cathedral heads is always a hot topic around here. A powerful LS2 can be build with either head but the rectangle set up will likely be tricker to get exactly right as Bortous mentioned.
Key Parts
TEA's Stage 2 LS6/243/799 program would be my choice for a coat effective, reliable, excellent results stock cube LS2 build. I'd want 11.5 to compression if you have 93 octane gas. Maybe a little more. The heads are well proven.
An expert ported Fast 92 intake with a port matched WARR 92 mm TB would round out the intake side. 1 7/8 long tube headers.
Cam will depend on what you want from the car.
Key Parts
TEA's Stage 2 LS6/243/799 program would be my choice for a coat effective, reliable, excellent results stock cube LS2 build. I'd want 11.5 to compression if you have 93 octane gas. Maybe a little more. The heads are well proven.
An expert ported Fast 92 intake with a port matched WARR 92 mm TB would round out the intake side. 1 7/8 long tube headers.
Cam will depend on what you want from the car.
It's just how it is.
Sure you can cam them differently but it makes hardly any difference to the way the car feels.
I went through this many times over the years with smaller camshafts trying to get the low and mid range punch back but I never got the result.
I also tried a custom camshaft from flowtech induction. As many of you know Ed knows his camshafts but even that grind improved things but it was never the same.
That low and mid range punch of the stock head was just not going to happen with the ls3 head. I even had 11:5.1 compression back then too.
I personally think the LS3 head will feel like like a cathedral head in the low and mid range if it was on an LS7 engine with the big bore and the cubes to really get the air flowing through those big ports quicker.
Might be right might be wrong. Just a theory.
The FAST 102mm in superior over the 90mm version.
The testing I have seen on the threads show that the FAST 102mm makes more hp and torque off idle to the red line compared to the early version.
I personally wouldn't bother with the 90mm.
Those TEA stage 2 heads. The flow they get on the stock head is one of the best I have seen for a stock casting.
Obviously not as efficient as the aftermarket AFR cathedrals but it is a good compromise and you will still make good power.
TECH Addict
Joined: Sep 2010
Posts: 2,898
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You can see the 403" LS2 that I am building for my 1992 Corvette, the build is here
https://ls1tech.com/forums/conversio...minator-x.html
Admittedly, I might have built this different, it didn't start out to be a 403, and I did the engine work 5-6 years ago.
Look at post 16, there is shows links to dynos of 383 and 408s with ported 243s and the same cam as mine, and some results in Tuskys cookbook thread of what people have done with ported 243s in the quarter.
In my application, I am building a street car, so I am ok with possible top end HP limitations of the ported stock heads, for what they should give me in lower throttle response and mid range. 600 HP was my goal and *plenty* for a C4.
I think the guys above have covered the issues with chamber size and PTV clearance.
https://ls1tech.com/forums/conversio...minator-x.html
Admittedly, I might have built this different, it didn't start out to be a 403, and I did the engine work 5-6 years ago.
Look at post 16, there is shows links to dynos of 383 and 408s with ported 243s and the same cam as mine, and some results in Tuskys cookbook thread of what people have done with ported 243s in the quarter.
In my application, I am building a street car, so I am ok with possible top end HP limitations of the ported stock heads, for what they should give me in lower throttle response and mid range. 600 HP was my goal and *plenty* for a C4.
I think the guys above have covered the issues with chamber size and PTV clearance.
It's a great build.
I like the combination of parts you have chosen.
If I had the right knowledge years ago I would have built the same engine as you.
The cam specs are also great for driveability and good rounded power.
I see you got the same cam specs as in that Richard Holdener video
TECH Addict
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You will be fine. Having a 4.155 bore and 434 cubes like me you could run either head and be good.
Although the ported 243 heads would still be stronger in the lower RPM ranges but the LS3 would feel way better than what mine did on my stock cubed LS2 that's for sure.
You are free from any criticism. Lol
Although the ported 243 heads would still be stronger in the lower RPM ranges but the LS3 would feel way better than what mine did on my stock cubed LS2 that's for sure.
You are free from any criticism. Lol
You will be fine. Having a 4.155 bore and 434 cubes like me you could run either head and be good.
Although the ported 243 heads would still be stronger in the lower RPM ranges but the LS3 would feel way better than what mine did on my stock cubed LS2 that's for sure.
You are free from any criticism. Lol
Although the ported 243 heads would still be stronger in the lower RPM ranges but the LS3 would feel way better than what mine did on my stock cubed LS2 that's for sure.
You are free from any criticism. Lol
I never considered anything but LS7 architecture, and designed the build long before I ever spent a dime.
Good to be criticism free however...
TECH Regular
Joined: Dec 2011
Posts: 420
Likes: 115
Here's a video that is close to your situation, although the dished LY6 pistons will drop the compression by about 1/2 point. This mirrors other tests I have seen. When its truly back to back, the catherdral ports usually are better up until 4000-4500, and then lose out at the top, when we are talking about the factory heads.
I have seen another test with an LQ4. so it compared 317s vs LS3s, the LQ4 was in front until 4000 rpm, and the LS3 eventually made 40hp more. Here it's 20 or so, that difference is the point of compression gained from the 799 over the 317.
One downside is that if you still have LS2 intake, its not good, and should be replaced to take advantage of any head porting. Since you are in Detroit metro area, Katech does CNC porting for $500 on your castings. I've been thinking about getting a set of 5.3 heads and having a quick port done on them, I have CNC'd 317 heads on my LQ4 in my Jimmy, but I'd like a little more compression and a little more cam.
I have seen another test with an LQ4. so it compared 317s vs LS3s, the LQ4 was in front until 4000 rpm, and the LS3 eventually made 40hp more. Here it's 20 or so, that difference is the point of compression gained from the 799 over the 317.
One downside is that if you still have LS2 intake, its not good, and should be replaced to take advantage of any head porting. Since you are in Detroit metro area, Katech does CNC porting for $500 on your castings. I've been thinking about getting a set of 5.3 heads and having a quick port done on them, I have CNC'd 317 heads on my LQ4 in my Jimmy, but I'd like a little more compression and a little more cam.
