1LE Hugger Orange

Do LS6 heads work on a LS1 engine and can I use the 4.7 stock pushrods ?

R6cowboy

iTrader: (3)

Plain and simple answer is yes. You can install factory LS6 heads on a factory LS1 shortblock and use the stock pushrods.

1LE Hugger Orange

Are there any power gains on using the LS6 heads on a LS1 engine ? I have a LS6 intake and a LG cam , 600/610 and about 240 duration with a comp cams double spring kit pushrods and a trunnion kit.

justin hover

Yeah...get those heads ported and you'll gain 20-40hp. Exactly what Im in the process of doing right now.

R6cowboy

iTrader: (3)

Absolutely, especially ported and with a valve job LS6 heads can make impressive power, but that could be said regarding any LS head really. Basically the LS6 heads are a step up from LS1 heads.

Here are the differences between the heads:

LS1 head (853 or 241 casting number)

Combustion Chamber Vol. : 66.67 cc
Compression Ratio : 10.1:1
Intake Port Vol. : 200 cc
Exhaust Port Vol. : 70 cc
Intake/Exhaust Valve : 2.00/1.55 inches

LS6/2 head (243 or 799 casting number)

Combustion Chamber Vol. : 64.45 cc
Compression Ratio : 10.5:1
Intake Port Vol. : 210 cc
Exhaust Port Vol. : 75 cc
Intake/Exhaust Valve : 2.00/1.55 inches

FWIW, LS6 heads with 243 casting number that came in the Corvette C5 Z06 had lighweight hollow stem intake valves and sodium filled exhaust valves with revised valve springs to match the LS6 cam's increased lift.

1LE Hugger Orange

Will my LS1 spring kit and trunnions work on a LS6?

R6cowboy

iTrader: (3)

Yes. Anything that will work on LS1 heads will work on LS6 heads. The head castings themselves are exactly the same, the only differences are the shapes of the combustion chambers, intake and exhaust runners. All hardware/valvetrain components are interchangable between the heads.

1LE Hugger Orange

Thank you , to everyone for your info .

DANOZ28

iTrader: (1)

ls1 valve springs are the weakspot on factory engine. bare min upgrade springs to ls6 , i wish i had better than ls6. my factory ls1 springs at 50k milage floated / fluttered at 5800 rpm. my ls6 springs with my ls6 cam (only 550 lift) never miss a heartbeat knock on wood! cheers.

Mercier

iTrader: (15)

LS6(2) springs are so cheap new($50-ish) that I rarely see LS6 or 243 heads without actual springs on them.. So you'll probably be in good shape if you find a good used set.

Stock 243s should be good for 20-30HP even unported right?

DANOZ28

iTrader: (1)

tsp told me my stage 1 ported heads (#243 ls6) were worth aprox 20 rwhp by themselves, after that depends on the cam choice. fwiw.

Mercier

iTrader: (15)

Were they comparing to stock 243s or stage 1 ported vs stock LS1 head(241/853/etc.)? I would expect ported 243 vs stock 241 to be a bigger difference? Maybe I am giving the 243 too much credit?

R6cowboy

iTrader: (3)

I think TSP was comparing their stage 1 ported 243s vs factory 243s, a 20whp increase on otherwise stock LS1 engine would be save to say. That makes sense. Also, I agree you're about right regarding factory 243s are worth about 20 some hp over factory 241s on an otherwise stock LS1.

DANOZ28

iTrader: (1)

im remembering from back in 2006 when i added heads. i believe that number was if i just added those heads to my stock 99 motor with stock cam. a better cam can take more advantage of better flowing heads.