Dustin AZ

iTrader: (1)

Sorry, guys, I couldn't find any information as far as to what gains might be with stock LS6 heads on a cammed (MS3) LQ9..

I'm not looking to spend $1,300+ on heads right now and was just wondering if the LS6 heads would offer significant HP gains over the stock 317 heads? I realize the compression ratio will be higher with smaller chambered head.


Thanks in advance!



- Dustin

PAGregSS

iTrader: (10)

Compression ratio is really the only difference. The 317s are pretty much the same design as the 243.

gearhead1186

iTrader: (8)

243/799 heads have 64cc combustion chambers. 317s have 71cc combustion chambers. if you have your heads off and happen to have 243s laying around id def throw em on but I wouldnt go to all the work of buying heads and doing the swap for only a couple points in compression.

1SLwLS1

iTrader: (6)

absolutely, I went from stock 241 heads on my LS1, 66.67cc, to 799 heads, 64.45cc. My compression jumped from 10.1:1 to 10.5:1 and picked up 25 across the board, much less adding 0.8:1 compression. I would definitely go for it.

NemeSS

iTrader: (127)

i would say yes.
mill the heads, cut in relives and run a bigger cam.
stock 243s are excellent performers.

kinglt-1

iTrader: (26)

241 heads dont flow aswell as 243s... The 317's flow the same as 243's, so the slight bump in compression will be worth a few hp, not 25 across the board. Just wanted to clear this up, not trying to start an argument.

1SLwLS1

iTrader: (6)

I understand completely, my point was, he would double the compression bump.

kinglt-1

iTrader: (26)

yes I agree, just did not want the op to think he was goin to gain 25 across the board from the swap...

1SLwLS1

iTrader: (6)

Rough figures would be 4-5%

kinglt-1

iTrader: (26)

yep he should see a 10-15 hp increase. I would say its worth it, especially if the op's got a few extra bucks to have the 243's cleaned up a bit.

firebirdlt1350

will the 243 heads work on a 08 lq9 motor also will it fit in a ls1 car or will i have to make some changes to the wiring harness