SiCk PuPpY
12-04-2005, 12:45 PM
I am in the proccess of building a F.I. LT1 355 that is projected see about 8-10 lbs of boost (Vortec V-1). Based on my calculations, the SCR came in at 9.7:1 based on the following:
52cc head chambers (clean-up cut/ 2.00 & 1.60 valves using stock seats)
4.030 bore
.039 fel-pro 1074s (4.125 hole)
-20cc wisecos
5.7 rod
3.48 stroke
deck hieght of .015 (assumed based on factory spec;I will doulbe-check how far the piston sits in the hole once the s.b. is assembled)
Accepted theory is that this CR is too high for a F.I. motor. Is DCR more important than SCR? I am researching how to reduce CR without raplacing the pistons. Here's what i've theorized thus far:
-The original valve seats were used, if I have larger seats installed to drop the valves deeper into the chamber, would that significantly increase the chamber volume enough?
-The Fel-Pros are .039 thick. Is there a thicker gasket on the market that will hold up to this moderate amount of boost?
-Can a significant amount of head chamber material be removed on the LT1 heads to reduce SCR?
This is my first F.I. build and I definatley chose the wrong pistons. -20cc was not enough to get to my target 9:1 cr, but replacing them isn't an option. If i'm stuck with this CR, then i'll just have to reduce the boost accordingly and have it tuned accordingly.
Any insight/advice would be greatly apprecieated.
Cheers,
John
52cc head chambers (clean-up cut/ 2.00 & 1.60 valves using stock seats)
4.030 bore
.039 fel-pro 1074s (4.125 hole)
-20cc wisecos
5.7 rod
3.48 stroke
deck hieght of .015 (assumed based on factory spec;I will doulbe-check how far the piston sits in the hole once the s.b. is assembled)
Accepted theory is that this CR is too high for a F.I. motor. Is DCR more important than SCR? I am researching how to reduce CR without raplacing the pistons. Here's what i've theorized thus far:
-The original valve seats were used, if I have larger seats installed to drop the valves deeper into the chamber, would that significantly increase the chamber volume enough?
-The Fel-Pros are .039 thick. Is there a thicker gasket on the market that will hold up to this moderate amount of boost?
-Can a significant amount of head chamber material be removed on the LT1 heads to reduce SCR?
This is my first F.I. build and I definatley chose the wrong pistons. -20cc was not enough to get to my target 9:1 cr, but replacing them isn't an option. If i'm stuck with this CR, then i'll just have to reduce the boost accordingly and have it tuned accordingly.
Any insight/advice would be greatly apprecieated.
Cheers,
John