402 Head gasket help needed
08-05-2006, 09:59 AM
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402 Head gasket help needed Been working with the DCR calculator and preparing for a cam swap for the 402. I already bought the cam so I need to decide on head gasket dimensions.
Hopefully my inputs were correct. Here they are for you to double check for me. What should I chose for a bore size? I listed a couple of options listed on Cometics website but I'm not sure what is proper?
4" bore
COMP 287/289 LSA=112+0
piston to deck -0.007
piston reliefs -6cc
From calculator
Thickness.........Bore.............DCR............ Quench
0.040......... 4.130......... 8.605......... .033
0.040......... 4.160......... 8.592......... .033
0.040......... 4.190......... 8.560......... .033
0.051 ......... 4.130 ......... 8.37 ......... .044
0.051 ......... 4.160 ......... 8.3562 ......... .044
0.051......... 4.190......... 8.341......... .044
0.055......... 4.130......... 8.29......... .048
0.055......... 4.160......... 8.27......... .048
0.055 ......... 4.190......... 8.25......... .048
Pretty Picture
I want the highest DCR with the best quench(don't know what's best) right? Fuels I can get are 93 & 94 octane I usually run 94 Sunoco. Please advise on the thermostat temp as well.
Hopefully my inputs were correct. Here they are for you to double check for me. What should I chose for a bore size? I listed a couple of options listed on Cometics website but I'm not sure what is proper?
4" bore
COMP 287/289 LSA=112+0
piston to deck -0.007
piston reliefs -6cc
From calculator
Thickness.........Bore.............DCR............ Quench
0.040......... 4.130......... 8.605......... .033
0.040......... 4.160......... 8.592......... .033
0.040......... 4.190......... 8.560......... .033
0.051 ......... 4.130 ......... 8.37 ......... .044
0.051 ......... 4.160 ......... 8.3562 ......... .044
0.051......... 4.190......... 8.341......... .044
0.055......... 4.130......... 8.29......... .048
0.055......... 4.160......... 8.27......... .048
0.055 ......... 4.190......... 8.25......... .048
Pretty Picture
I want the highest DCR with the best quench(don't know what's best) right? Fuels I can get are 93 & 94 octane I usually run 94 Sunoco. Please advise on the thermostat temp as well.
Last edited by squealingtires; 08-05-2006 at 10:10 AM.
08-05-2006, 12:10 PM
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Take a look here http://www.popularhotrodding.com/tec...on_ratio_tech/
.. and get yourself a 160* thermostat
Lowest quench is good. Heads, plugs etc also affect optimal compression.
.. and get yourself a 160* thermostat
Lowest quench is good. Heads, plugs etc also affect optimal compression.
08-06-2006, 12:09 AM
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Originally Posted by See5
I think with a stock 4.0 bire you want to use 4.03" gaskets. Also what is your head volume?
62.88cc . I wasn't sure what the best size was for gaskets. It didn't make any sense to me as to why anyone would use a gasket larger than 4.03 for a 4 inch bore but then I figured that the pistion negative deck height had something to do with it. My DCR is going to be way up there with a 4.03 gasket. I'll repost with the new measurements.
