replacing 241 heads for 317 heads.

**ssprochargedss** · 03-05-2012, 06:50 PM

i bought my car with a p1s procharger on it and i have a set of 241 heads on my car already. I want to bolt on this set of 317 heads i have. will this help my car? I read that there exact same as 243 heads just with bigger combustion chambers./ will i gain power or will this compresstion thing loose power?

**ICRAZY6** · 03-07-2012, 08:51 AM

It will be safer on a stock rotating assy, dropping the compression for a more boost friendly compression ratio. How much boost are you running?

**JoshuaGrooms83** · 08-05-2012, 02:03 PM

was wondering abuot this too. whats the out of boost response though with the 317s?

**JoshuaGrooms83** · 01-04-2013, 09:00 PM

did a little math messing around and somewhat got what the CR would be on stock LS1 with only the heads and gaskets changed. stock 317s and differnt head gaskets.

LS1 stock combustion chamber
Cylinder Bore Size 3.898
Piston Stroke Length 3.622
Head Gasket Bore Diameter 4.10
Compressed Head Gasket Thickness 0.058
Combustion Chamber Volume In CCs 66
Piston Dome Volume In CCs Negative For Dished Pistons (Use '-') 0
Piston Deck Clearance Negative If ABOVE Deck (Use '-') : -0.007
CR= 10.1:1

with 317 heads 71cc, stock gasket .058, 9.6:1 CR
with 317 heads 71cc, LS9 gasket .051, 9.7:1 CR (probably the better of the 3 for boost apps)
wtih 317 heads 71cc, Cometic .040, 10:1 CR

with this in mind, 317 heads on stock ls1 block and boost is not a bad trade off. add a mild cam and a touch more boost and any low end N/A lost is quickly negated. im doing this for my car