243 vs 853 How much gain for unported heads
08-30-2009, 08:19 PM
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243 vs 853 How much gain for unported heads What kind of real power gain should I expect from a stock 243 head without sodium valves.A friend of mine has a new set for $600.00 Money is a little tight right now so aftermarket heads are out of the question.I have stock 853 heads now. What gains should I see if I have them ported and who should I get to port them,I dont want some knucklehead hogging them out that has no experience with ls heads. Thinking about milling to bump compression what should I consider max. compression for 93 octane.Locally I mix a little 110 with each tank but when on trips who knows what we get. What do you think 11.1 or 11.5 compression. I'M NEW SO LET ME HAVE IT.
99 formula
stock short block
thunder racing 230-236 592-600 112lsa 650'' springs chromemoly pushrods
long tubes
weiand lingenfelter intake
ud crank pulley
msd wires
ls6 oil pump
3'' exhaust with cutout
lightened flywheel
spec stage 3 clutch
spohn torque arm
bmr trailing arms
pst driveshaft
strange 12 bolt 4.10 33 spline axles
qa1 shocks front and rear
line lock
car dynoed 384 rwhp on mustang dyno
traps 115-116 in 1/4
99 formula
stock short block
thunder racing 230-236 592-600 112lsa 650'' springs chromemoly pushrods
long tubes
weiand lingenfelter intake
ud crank pulley
msd wires
ls6 oil pump
3'' exhaust with cutout
lightened flywheel
spec stage 3 clutch
spohn torque arm
bmr trailing arms
pst driveshaft
strange 12 bolt 4.10 33 spline axles
qa1 shocks front and rear
line lock
car dynoed 384 rwhp on mustang dyno
traps 115-116 in 1/4
Last edited by 74ta; 08-30-2009 at 08:50 PM. Reason: more questions
08-30-2009, 08:43 PM
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I've seen people say different ranges on power....Some people say 10-20rwhp, some say 15-25rwhp...
I'm not sure how much you could mill and avoid piston-to-valve contact. Maybe 0.020??? Or you could run a thinner head gasket like the Cometic MLS .040 thick gasket.
If it was me, I wouldn't pay $600 for a set of the heads even if they were new. I've seen some slightly used LS2 243 heads for $250-300... but they sell quick.
Recently, I bought some 799 heads for $200. Sold the valve covers and rocker arms for $80, and have $120 invested in some good heads, so far..hah. The 799 heads come on H.O. 5.3L and some LS2 Corvettes.
I'm not sure how much you could mill and avoid piston-to-valve contact. Maybe 0.020??? Or you could run a thinner head gasket like the Cometic MLS .040 thick gasket.
If it was me, I wouldn't pay $600 for a set of the heads even if they were new. I've seen some slightly used LS2 243 heads for $250-300... but they sell quick.
Recently, I bought some 799 heads for $200. Sold the valve covers and rocker arms for $80, and have $120 invested in some good heads, so far..hah. The 799 heads come on H.O. 5.3L and some LS2 Corvettes.
