JeaneGrae

iTrader: (7)

A set of 317's or 243's? Pretty much on a mild cammed, full bolt on ls1? pros/cons of both please.

Silver_TransAm

iTrader: (2)

They flow the same and have the same port size 210/75cc. The only diff is the combustion chamber volume. 64.45 for the 243 and 71.06 for the 317. The 317s are good for forced induction due to the lower compression.

If you plan on staying all motor go with the 243 ls6 head.

JBIRD02

iTrader: (4)

I'm no expert, and haven't seen any back to back tests, but this is what I was always told too. They are basically the same except the 243's have a smaller cc volume. I've seen a lot of forced induction guys go with the 317's for the reason listed above as well.

JeaneGrae

iTrader: (7)

So on a NA engine would the 317's with lower compression hurt performance? If so how much ?

jsteele90

iTrader: (13)

just get the 243s for all motor and the 317s for boost

carzmed

iTrader: (3)

Compression is power, if you are going to buy new pistons then you can tailor the compression to be what you want it to be.

greatskiiiier

iTrader: (10)

^ compression= power, all mods are to boost oxygen and compression, thats why S/C and T/C are such big power-adders

SlwSVT

All things being equal, the 243 heads will make more power under the curve due to the higher compression. If you are staying N/A go with the 243 heads, maybe even add a thinner head gasket to raise compression. If you have any plans for forced induction go with the 317 heads, it will help when you do add boost.