Mild LS2 build with LS3 heads/intake
Thread Starter
Intermediate
Joined: Feb 2023
Posts: 25
Likes: 8
From: Mississippi
Mild LS2 build with LS3 heads/intake
Okay guys I have a 2007 C6 with the LS2 (automatic) and 90k miles on it in my vette cart/drift buggy. One of the guys in my shop is about to build an LS3 in a 2011 C6 with 80k on it and will be pulling the heads/intake as he is doing new heads/hiram/cam/etc. on this build so I was going to swap the LS3 heads/intake onto my LS2. I've got a custom car shop but I am more a cosmetic/suspension/interior/upfitter and definitely not an engine builder so I want to make sure I get everything I need and refresh anything needed.
Here's the plan:
LS3 Heads/Manifold (was not going to port them as I am not pushing for crazy HP but if there are flow issues and recommended can have it done)
Mild cam (recommendations?)
Ported LS3 throttle body
Headers
And then have my tuner retune it after
Anything else needed other than heads/intake/throttle body to work on my LS2 C6?
Are the throttle body connections the same for LS2/LS3 or do I need a wiring adapter?
Anything else recommended to replace while doing all this? Oil pump?
Any help would be greatly appreciated
Spencer
Here's the plan:
LS3 Heads/Manifold (was not going to port them as I am not pushing for crazy HP but if there are flow issues and recommended can have it done)
Mild cam (recommendations?)
Ported LS3 throttle body
Headers
And then have my tuner retune it after
Anything else needed other than heads/intake/throttle body to work on my LS2 C6?
Are the throttle body connections the same for LS2/LS3 or do I need a wiring adapter?
Anything else recommended to replace while doing all this? Oil pump?
Any help would be greatly appreciated
Spencer
Instructor
Joined: Jan 2006
Posts: 224
Likes: 72
From: Rocky Mountains USA
Just use your LS2 throttle. Its probably silver blade vs later LS3 brass blade, so different. Same size anyway.
Cam. Peoples definition of mild varies.
LS9 cam is like 211/230
Id probably not go much bigger than 220/232 check out cammotion mild ls3 cams
https://cammotion.com/camshafts/mild...-ls-camshafts/
Dont forget the rockers, lifters and pushrods, head gaskets, timing set etc as well
Cam. Peoples definition of mild varies.
LS9 cam is like 211/230
Id probably not go much bigger than 220/232 check out cammotion mild ls3 cams
https://cammotion.com/camshafts/mild...-ls-camshafts/
Dont forget the rockers, lifters and pushrods, head gaskets, timing set etc as well
Le Mans Master
Joined: Dec 2005
Posts: 7,002
Likes: 1,687
From: Southeast TX
I think I'm wasting my breath here, but I'll throw this out for posterity's sake. If you put stock LS3 heads on an LS2 with an itty bitty cam, you're wasting your time and money. Your static CR is going down...by quite a bit. You're losing power, fuel eco, and drivability right there. A cam not specced specifically for this change exasperates this. You're better off porting your stock heads, adding a FAST intake manifold, along with the itty bitty cam. WAY better use of funds.
Just to be clear, I'm not a fan of big cams on street Vettes. Far from it.
Just to be clear, I'm not a fan of big cams on street Vettes. Far from it.
Drifting
Joined: Jul 2007
Posts: 1,294
Likes: 37
LS3 heads on a LS2
I have Texas Speed stage 4 cam (F-35). At first I had the stock ls2 heads and switched them out with stock Ls3 heads. Holy ****. The mid to high range is ridiculous now. I feel for certain I picked up an entire second in the quarter. That’s with the lower compression as I didn’t shave them at all. Planning to stroke engine and shave heads for additional HP.
I think I'm wasting my breath here, but I'll throw this out for posterity's sake. If you put stock LS3 heads on an LS2 with an itty bitty cam, you're wasting your time and money. Your static CR is going down...by quite a bit. You're losing power, fuel eco, and drivability right there. A cam not specced specifically for this change exasperates this. You're better off porting your stock heads, adding a FAST intake manifold, along with the itty bitty cam. WAY better use of funds.
Just to be clear, I'm not a fan of big cams on street Vettes. Far from it.
Just to be clear, I'm not a fan of big cams on street Vettes. Far from it.
Last edited by JimiHendrix; Aug 3, 2024 at 03:00 PM.
Le Mans Master
Joined: Jan 2001
Posts: 6,451
Likes: 371
From: Maryville TN
St. Jude Donor '06-13,'16-'17, '19
Le Mans Master
Joined: Dec 2005
Posts: 7,002
Likes: 1,687
From: Southeast TX
Some say a really good tuner can tune out all of those bad attributes of a big cam. That hasn't been my experience at all. Just imagine how good your Vette can run with a more moderate cam tuned by that same genius tuner.
The big nasty cams lose power on the streets in the rpm band that you actually use and only show increases above 5500 rpm vs a more moderate cam. Again, some may like that. Just ain't for me.
You can go too small on a cam swap also. What's the point? Cam swaps are expensive, especially if you hire everything done. Add all the other things to make your LS powered Vette a fun street ride and then choke it with a 220 and under cam just doesn't make sense to me.
Safety Car
Joined: May 2016
Posts: 4,672
Likes: 1,851
From: Erlanger, Kentucky
Okay guys I have a 2007 C6 with the LS2 (automatic) and 90k miles on it in my vette cart/drift buggy. One of the guys in my shop is about to build an LS3 in a 2011 C6 with 80k on it and will be pulling the heads/intake as he is doing new heads/hiram/cam/etc. on this build so I was going to swap the LS3 heads/intake onto my LS2. I've got a custom car shop but I am more a cosmetic/suspension/interior/upfitter and definitely not an engine builder so I want to make sure I get everything I need and refresh anything needed.
Here's the plan:
LS3 Heads/Manifold (was not going to port them as I am not pushing for crazy HP but if there are flow issues and recommended can have it done)
Mild cam (recommendations?)
Ported LS3 throttle body
Headers
And then have my tuner retune it after
Anything else needed other than heads/intake/throttle body to work on my LS2 C6?
Are the throttle body connections the same for LS2/LS3 or do I need a wiring adapter?
Anything else recommended to replace while doing all this? Oil pump?
Any help would be greatly appreciated
Spencer
Here's the plan:
LS3 Heads/Manifold (was not going to port them as I am not pushing for crazy HP but if there are flow issues and recommended can have it done)
Mild cam (recommendations?)
Ported LS3 throttle body
Headers
And then have my tuner retune it after
Anything else needed other than heads/intake/throttle body to work on my LS2 C6?
Are the throttle body connections the same for LS2/LS3 or do I need a wiring adapter?
Anything else recommended to replace while doing all this? Oil pump?
Any help would be greatly appreciated
Spencer
You will need new head gaskets. I would go with factory GM LS3 MLS gaskets.
You will also need a set of valve springs to go with that cam. Cam Motion's .625 lift beehive springs would be excellent.
I recommend replacing your valve seals when you swap out the springs. They are cheap and very easy to change out.
You should also change out your cam retainer plate. It is a cheap part and will ensure that you have good oil pressure.
If your engine has good oil pressure now, no need to change out the pump.
With 90K on your engine, you could put in a new set of lifters with the cam. Factory LS7 lifters or even some Chevy race or "Caddy" lifters would be excellent. Make sure to put in new lifter trays. If you want to go all out, a set of Johnson link bare lifters would be awesome but they are not cheap.
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Le Mans Master
Joined: Dec 2005
Posts: 7,002
Likes: 1,687
From: Southeast TX
Do something like this...TxSpeed heads and mild cam build - CorvetteForum - Chevrolet Corvette Forum Discussion
Substitute a 224/230 115+4 .610/.610 for the cam I used. That build has been going strong for 5 years or so. Little bit of a rough idle, but perfect manners. Runs really strong too.
Substitute a 224/230 115+4 .610/.610 for the cam I used. That build has been going strong for 5 years or so. Little bit of a rough idle, but perfect manners. Runs really strong too.
Drifting
Joined: Jul 2007
Posts: 1,294
Likes: 37
I didn't feel any loss of power in the lower rpm. I think it's because the Ls3 intake flows better at all rpm levels vs Ls2 intake. But I understand why many don't like a big nasty screamy cam. Just like some guys don't like big ****.....
I love cammed street cars. My 2013 is a heads/cam car. I hate big/high overlap cams that ruin two of the attributes I like about Vettes. I like smooth, efficient, and quick. While big overlap cams make the juice...no doubt, they take away the smooth and efficient though. That's unacceptable to me. Some guys like that. I don't. At all.
Some say a really good tuner can tune out all of those bad attributes of a big cam. That hasn't been my experience at all. Just imagine how good your Vette can run with a more moderate cam tuned by that same genius tuner.
The big nasty cams lose power on the streets in the rpm band that you actually use and only show increases above 5500 rpm vs a more moderate cam. Again, some may like that. Just ain't for me.
You can go too small on a cam swap also. What's the point? Cam swaps are expensive, especially if you hire everything done. Add all the other things to make your LS powered Vette a fun street ride and then choke it with a 220 and under cam just doesn't make sense to me.
Some say a really good tuner can tune out all of those bad attributes of a big cam. That hasn't been my experience at all. Just imagine how good your Vette can run with a more moderate cam tuned by that same genius tuner.
The big nasty cams lose power on the streets in the rpm band that you actually use and only show increases above 5500 rpm vs a more moderate cam. Again, some may like that. Just ain't for me.
You can go too small on a cam swap also. What's the point? Cam swaps are expensive, especially if you hire everything done. Add all the other things to make your LS powered Vette a fun street ride and then choke it with a 220 and under cam just doesn't make sense to me.
Le Mans Master
Joined: Dec 2005
Posts: 7,002
Likes: 1,687
From: Southeast TX
