LS1 block with LS6 heads *only*
Thread Starter
Former Vendor
Joined: Nov 2005
Posts: 8,995
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From: Spring Texas
St. Jude Donor '08
LS1 block with LS6 heads *only*
How would swapping out the heads on my 97 for a set of LS6 heads affect my power? Where portion of the powerband would be affected most? Aside from the heads themselves, what other parts would i need to do the swap?
Melting Slicks
Joined: Jan 2007
Posts: 3,333
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From: Athens OH
I can't comment on the power difference, but I can tell you some of the things you will need.
The LS6 heads are a center bolt valve cover as opposed to the perimeter bolt VC on the LS1 so you will need VC.
On the LS1 heads, the coils mount directly to the VC. The LS6 coils have a mounting bracket that bolts to the VC and the coils bolt to that bracket. If the VC you buy don't have the brackets, you will need them as well. I was able to use my coils and harness, but I ende dup having to rotate one of the coils 180 degrees. I can get some pics tonight if it helps.
The LS6 heads are a center bolt valve cover as opposed to the perimeter bolt VC on the LS1 so you will need VC.
On the LS1 heads, the coils mount directly to the VC. The LS6 coils have a mounting bracket that bolts to the VC and the coils bolt to that bracket. If the VC you buy don't have the brackets, you will need them as well. I was able to use my coils and harness, but I ende dup having to rotate one of the coils 180 degrees. I can get some pics tonight if it helps.
Pro
Joined: Jul 2007
Posts: 650
Likes: 15
From: Jupiter Florida
valve covers? i didnt need new valve covers. the only thing i needed for the swap was new head gaskets? of course i added arp head studs when i put it back together.
to the op as far as power i cant answer that. i did worked ls6 heads so it wouldnt be a fair comparrison to stock ls6 heads.
to the op as far as power i cant answer that. i did worked ls6 heads so it wouldnt be a fair comparrison to stock ls6 heads.
Melting Slicks
Joined: Jan 2007
Posts: 3,333
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From: Athens OH
The VC may be not be different between LS1 and LS6. It may be different between later years. He has a 98 car and I am pretty sure that model does originally has perimeter bolt VC so he should still need the VC.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
You will need new valve covers. The original 806 heads were power limiting so I think this would be a nice upgrade. I would guess 25 hp could be netted from this swap. More if you want to mill them down for more compression and run a 0.040" head gasket. Your mileage might go up as well from the additional compression.
Racer
Joined: Jul 2006
Posts: 285
Likes: 1
From: Placentia CA
I replaced the 241 heads on my 02 with 243 heads from an 03 Z. All I did to the heads was an old fashion 3 angle valve grind. Don’t have any numbers but seat of the pants says 15 HP with the extra pull starting 2,500 or so. I would think your gains should be a little more as you’re starting with 806 heads. Another plus is it’s cool to open your hood and see that “243” on the front of the right head! 
Remember too that if they are 02-04 LS6 heads they will have the longer (about .025) hollow stem valves. I know some guys just use the stock pushrods and let the lifter suck it up but really it should have little shorter pushrod. Thinking about valve train geometry can drive you “vettenuts”. Seriously he is the man to ask about anything valve – rocker arm – pushrod – cam base circle etc.
Remember too that if they are 02-04 LS6 heads they will have the longer (about .025) hollow stem valves. I know some guys just use the stock pushrods and let the lifter suck it up but really it should have little shorter pushrod. Thinking about valve train geometry can drive you “vettenuts”. Seriously he is the man to ask about anything valve – rocker arm – pushrod – cam base circle etc.
