help calculating head gasket thickness, compression 403
#1
help calculating head gasket thickness, compression 403
hey guys-
looking for some assistance putting together the details for my 403 that is going into my vette. short block details:
LS2 403" Stroker Shortblock
4.000" Stroke CompStar Crankshaft
6.125" CompStar H-Beam Rods w/ARP2000 Hardware
4.005" Bore -28cc Dish Diamond Piston Set
Total Seal Piston Rings w/Steel Top
Melling high volume oil pump
Billet double roll timing set
Comp cam
Spec card #06751604
Grind # LS1 3726/3728
281/285 adv
232/236 @ .050";
.595/.601" lift;
114 degree LSA, ground with a 114 degree intake center line.
i plan to use my c&c-ed 853 casting heads and a ported FAST 90/92...not sure on what thickness headgasket i'm going to need, or if i will need to mill the heads to up compression. shortblock was built for boost but i want to keep the car NA...i got a killer deal on the shortblock.
suggestions? thanks
looking for some assistance putting together the details for my 403 that is going into my vette. short block details:
LS2 403" Stroker Shortblock
4.000" Stroke CompStar Crankshaft
6.125" CompStar H-Beam Rods w/ARP2000 Hardware
4.005" Bore -28cc Dish Diamond Piston Set
Total Seal Piston Rings w/Steel Top
Melling high volume oil pump
Billet double roll timing set
Comp cam
Spec card #06751604
Grind # LS1 3726/3728
281/285 adv
232/236 @ .050";
.595/.601" lift;
114 degree LSA, ground with a 114 degree intake center line.
i plan to use my c&c-ed 853 casting heads and a ported FAST 90/92...not sure on what thickness headgasket i'm going to need, or if i will need to mill the heads to up compression. shortblock was built for boost but i want to keep the car NA...i got a killer deal on the shortblock.
suggestions? thanks
#3
853's that have been cnc-ed...what do you mean by soggy? would a different cam be more beneficial?
Last edited by andy9743; 06-12-2013 at 02:18 PM.
#4
TECH Veteran
iTrader: (3)
With that set up, a head gasket isn't going to bump your compression enough to put you in the ball park. With a 66cc combustion chamber, and a .045" thick gasket with a 4.060 bore, your sitting at 9.05:1 static compression and a 6.72:1 dynamic compression. That is crazy low for a NA car
#5
With that set up, a head gasket isn't going to bump your compression enough to put you in the ball park. With a 66cc combustion chamber, and a .045" thick gasket with a 4.060 bore, your sitting at 9.05:1 static compression and a 6.72:1 dynamic compression. That is crazy low for a NA car
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#9
TECH Senior Member
With stock chambers 66.67and .052 gaskets,that would get you 11:1
#14
does .005 sound correct?
Last edited by andy9743; 06-13-2013 at 08:15 AM.
#16
#17
TECH Senior Member
Yes I meant just that. Piston position at TDC with respect to block deck. So are you assuming .005 or is that measured? See that makes a difference in the compression calculations.
IMO -28cc dish is too much for NA setup. -2 cc valve reliefs would be enough.
Cam is a bit small, but would make a nice driver with plenty trq; are you considering a swap?
I would choose more overlap, something around 11* positive to 15* positive.
IMO -28cc dish is too much for NA setup. -2 cc valve reliefs would be enough.
Cam is a bit small, but would make a nice driver with plenty trq; are you considering a swap?
I would choose more overlap, something around 11* positive to 15* positive.
#18
Yes I meant just that. Piston position at TDC with respect to block deck. So are you assuming .005 or is that measured? See that makes a difference in the compression calculations.
IMO -28cc dish is too much for NA setup. -2 cc valve reliefs would be enough.
Cam is a bit small, but would make a nice driver with plenty trq; are you considering a swap?
I would choose more overlap, something around 11* positive to 15* positive.
IMO -28cc dish is too much for NA setup. -2 cc valve reliefs would be enough.
Cam is a bit small, but would make a nice driver with plenty trq; are you considering a swap?
I would choose more overlap, something around 11* positive to 15* positive.
predator z check your pm's
thanks
#19
suggestions on what direction to go with pistons? idk if i really need to go with forged pistons for what i'm looking to achieve. whats out there in the 4.005 bore? what is cost effective for a dd type status? i'm not going to race the car, the current crank rods were set up by the po, it's most likely overkill for me. hyperutectic an option in 4.005 bore? thoughts on that? i found some wiseco's for $700 but idk if they would be overkill for my application. i know the c&ced 853's are going to hold me back but that's not the end of the world, i just want a well put together combo that makes respectable power. if i need to change the cam i can, if i need to change the pistons i can, if i can save the cam great...i think the pistons have to be swapped though from what i'm feeling here. intake is a mamo ported FAST unit, with an ls2 tb.