Quote:
Originally Posted by B4C
383 Ls1 block 11:9:1 CR
4" Callies Compstar crank
6.125 Callies Compstar rods
3.905 -3cc Diamond pistons
63cc Trickflow 220 heads w/PRC .650 dual springs
BTR pushrods
ARP bolts throughout
BTR custom grind cam 243/250 .623/.615 112+4
FAST 102mm intake (port matched)
FAST 92mm throttle body
FAST 46lb injectors (factory ls2/3 rail)
Powerbond UD pulley
Double roller billet timing set
SLP ported oil pump
That's all I know about the engine. Guy was parting his car on tech and I bought it off him.
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You need to find out head gasket thickness.
You need to know cam duration @ .006 lift to calc/estimate DCR. I dont see a shelf-available grind come up in googling those specs so Im guessing its a custom cam that may have proprietary lobes. My best guess based on comps lobe charts I am coming up with the following:
Assume 63cc, .005" OOTH, 74.5 IVC @.006,
0.030" gasket (concerning piston clearance):
12.07:1 SCR
8.87:1 DCR
Assume 63cc, .005" OOTH, 74.5 IVC @.006,
0.040" gasket (My preference):
11.77:1 SCR
8.66:1 DCR
Assume 63cc, .005" OOTH, 74.5 IVC @.006,
0.045" gasket:
11.63:1 SCR
8.56:1 DCR
Assume 63cc, .005" OOTH, 74.5 IVC @.006,
0.051" gasket (stock gasket thk):
11.46:1 SCR
8.44:1 DCR
Where did you get the 11.9:1 SCR from?
My general research:
91 octane: 8.5:1 DCR
92 octane: 8.5-8.6:1 DCR
93 octane: 8.7-8.8:1 DCR
Personally Ive run 8.88:1 DCR on an LS1, and 8.72:1 on an LS2 without issues running 93 pump.