LS3 LS7 head interchange - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

4xchamp · 01-02-2011, 11:02 AM

Can cyl heads be swapped between these engines ?

2SSRS@Gen5diy · 01-02-2011, 11:12 AM

Here you go.

Quote:

Well..........they might work But I would not try unless you are willing to take a risk.

What these guys posted is true, the LS7 heads are designed for the larger bore.

But.... I wondered just how close they are. I could not get a real answer from anyone.
I have a LS3 on the engine stand. So I thought "what the hell". I dropped a piston out of #5. I then bolted a L7 head on the block with an LS7 gasket. The intake valves clear by a bunch. The exhaust valve is within .020 to .030 from the cylinder wall. THe chamber also is larger than the bore but that doesn't hurt that much hehe.

As close as the exhaust valve is to the cylinder wall it probably hurts the flow just a little bit.

I might have to try it when I have some spare time.

Robin

Kilo-9 · 01-02-2011, 12:16 PM

If you try the LS7 heads, you will also need an LS7 intake. The intake ports on the LS7 heads are different than those on the LS3. Instead of LS7 heads, I would either have the LS3 heads ported/polished or go with an aftermarket casting that's designed for the smaller bore of the LS3 (like Mast or PRC). Just my .02.

Tampa Tuning · 01-02-2011, 12:43 PM

If wouldnt spend the money on differant heads OEM or aftermarket. The LS3 heads flow GREAT. If I did anything, Id just have them ported and polished to remove some flashing, but they are great flowing heads.

4xchamp · 01-04-2011, 07:45 PM

I was wondering if LS3 heads would bolt on to the Vette 427 and I guess they do as long as you run an LS3 intake

danhr · 01-04-2011, 08:31 PM

Quote:

Originally Posted by 4xchamp

I was wondering if LS3 heads would bolt on to the Vette 427 and I guess they do as long as you run an LS3 intake

they do.... quite a few people have done it on their cars on ls1tech...

don't see why but it is a combination that's been done.

Jason 98 TA · 01-05-2011, 08:25 AM

You will be able to run LS7 style heads on LS3 engines very shortly. I already have a LS7 configuration head going together in our new PRC castings that will have LS3 friendly valve locations! I flowed one yesterday at over 390cfm on a 4.065" LS3 bore plate!

I hope to have them dyno testing in 1-2 weeks!

JJ2010 · 01-05-2011, 08:41 AM

Nice....

JANNETTYRACING · 01-05-2011, 09:21 AM

Quote:

Originally Posted by 4xchamp

Can cyl heads be swapped between these engines ?

You can always CNC port your LS3 heads and Keep things simple.

We have a CNC program for LS3 heads.

Ted.

CC Performance · 01-05-2011, 10:03 AM

Yes you can interchange heads to answer your question but the LS7 heads need a 4.125 bore and your LS3 is a 4.065 as well as the intake difference ( the intake is an easy swap over)

We have an LS3 416 we are building for someone and he is going with AI to port his heads. We usually use TEA but we are very interested to see the results from the AI heads. Then you have aftermarket solutions.. TSP posted up their newest offering and there are the MAST heads that see really good results as well.

S-eatin-grin · 01-05-2011, 01:33 PM

If you were going to go to a 416 ci what size would you CNC port the stock LS3 heads to if running forced induction at 7.5 to 8 psi boost?

danhr · 01-05-2011, 01:42 PM

Quote:

Originally Posted by S-eatin-grin

If you were going to go to a 416 ci what size would you CNC port the stock LS3 heads to if running forced induction at 7.5 to 8 psi boost?

8

JANNETTYRACING · 01-05-2011, 01:58 PM

Quote:

Originally Posted by S-eatin-grin

If you were going to go to a 416 ci what size would you CNC port the stock LS3 heads to if running forced induction at 7.5 to 8 psi boost?

We would not run a 416 with only 8 psi, it would be more like 12-16 PSI

We port differently for Boosted VS N/A.

I don't know if we can quantify it in Size, because size is not a direct relation to Flow.

Ted.

S-eatin-grin · 01-05-2011, 02:15 PM

Sorry Ted...but now I'm totally confused...I thought high boost in FI led to blow ups in unforged LS3's/L99's?? I've read about lots of folks on here talking about blower cams being beneficial because they lower boost. Then I've also read that superchargers make their power by making boost. So adding a blower cam to a SC can cause loss of power if you don't pulley down? I need a nap and a year or two in performance auto mechanics...

01-02-2011, 11:02 AM	#1
4xchamp MURC 666 Drives: 69 Pace Car 68 Camaro Restomod 81 Z Join Date: Jan 2010 Location: New England , U.S.A. Posts: 480	LS3 LS7 head interchange Can cyl heads be swapped between these engines ? __________________ Guys hoarding their Camaros are depriving some youngster the opportunity to restore it 25 years from now . Drive it like you stole it , let the next guy baby it !

01-02-2011, 12:16 PM	#3
Kilo-9 Dog Is My Copilot Drives: 2011 2SS/RS LS3 Join Date: Jun 2009 Location: Pittsburgh, PA Posts: 1,394	If you try the LS7 heads, you will also need an LS7 intake. The intake ports on the LS7 heads are different than those on the LS3. Instead of LS7 heads, I would either have the LS3 heads ported/polished or go with an aftermarket casting that's designed for the smaller bore of the LS3 (like Mast or PRC). Just my .02. __________________

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Tampa Tuning Account Suspended Drives: TAMPA TUNING FACEBOOK & INSTAGRAM Join Date: Oct 2010 Location: Tampa, Fl Posts: 3,044	If wouldnt spend the money on differant heads OEM or aftermarket. The LS3 heads flow GREAT. If I did anything, Id just have them ported and polished to remove some flashing, but they are great flowing heads.

01-04-2011, 07:45 PM	#5
4xchamp MURC 666 Drives: 69 Pace Car 68 Camaro Restomod 81 Z Join Date: Jan 2010 Location: New England , U.S.A. Posts: 480	I was wondering if LS3 heads would bolt on to the Vette 427 and I guess they do as long as you run an LS3 intake __________________ Guys hoarding their Camaros are depriving some youngster the opportunity to restore it 25 years from now . Drive it like you stole it , let the next guy baby it !

01-05-2011, 08:25 AM	#7
Jason 98 TA Drives: Camaro Join Date: Apr 2009 Location: Texas Posts: 1,669	You will be able to run LS7 style heads on LS3 engines very shortly. I already have a LS7 configuration head going together in our new PRC castings that will have LS3 friendly valve locations! I flowed one yesterday at over 390cfm on a 4.065" LS3 bore plate! I hope to have them dyno testing in 1-2 weeks!

01-05-2011, 08:41 AM	#8
JJ2010 Drives: 2010 Camaro SS Join Date: Oct 2008 Location: Smithfield,NC Posts: 1,203	Nice....

01-05-2011, 10:03 AM	#10
CC Performance Account Suspended Drives: 99 Camaro SS, 79 z28, 70 GTX Join Date: Oct 2009 Location: ST Helens, OR Posts: 1,759	Yes you can interchange heads to answer your question but the LS7 heads need a 4.125 bore and your LS3 is a 4.065 as well as the intake difference ( the intake is an easy swap over) We have an LS3 416 we are building for someone and he is going with AI to port his heads. We usually use TEA but we are very interested to see the results from the AI heads. Then you have aftermarket solutions.. TSP posted up their newest offering and there are the MAST heads that see really good results as well.

01-05-2011, 01:33 PM	#11
S-eatin-grin Drives: 2013 2SS/RS AGM Join Date: Nov 2010 Location: WV Posts: 1,170 View My Garage	If you were going to go to a 416 ci what size would you CNC port the stock LS3 heads to if running forced induction at 7.5 to 8 psi boost?

01-05-2011, 02:15 PM	#14
S-eatin-grin Drives: 2013 2SS/RS AGM Join Date: Nov 2010 Location: WV Posts: 1,170 View My Garage	Sorry Ted...but now I'm totally confused...I thought high boost in FI led to blow ups in unforged LS3's/L99's?? I've read about lots of folks on here talking about blower cams being beneficial because they lower boost. Then I've also read that superchargers make their power by making boost. So adding a blower cam to a SC can cause loss of power if you don't pulley down? I need a nap and a year or two in performance auto mechanics...