General Category > Quadrajet Carb Talk and Tips
cam selection
tayto:
Thanks for the help cliff. Will let you know how engine turns out in the next few months. get block back from getting decked and crankshaft balanced next week then can start assembly.
FYI, apparently the 90-92 "773" TPI cam is the same duration and LSA but has about .010" more net lift VS the the 87-89 "643" TPI cam that I purchased. I have a feeling the later cam does not have a fuel pump lobe but have not seen one to verify.
tayto:
Cliff, finally got short block assembled, will be degreeing cam in the next few weeks. Do I want to install it "straight up"? due to it being a factory cam, I have no cam card. are the duration @ .050" enough for me to degree correctly?
Cliff Ruggles:
Yes, I always install them "dot to dot" and in most cases don't have to move them, but I do use factory timing sets, not aftermarket as they tend to be more accurate....
tayto:
I am using the "heavy duty" GM timing set that came on the roller motors.
tayto:
Cliff, I have measured my deck to piston height on my short block. I took a measurement on the left, then right of each piston added the values and divided by 2 to get an average. It varies cylinder to cylinder from .0125" to .0165" in the hole. Probably what I get for using cheap summit brand pistons or budget Eagle rods. Originally I was going to run the .028" GM head gaskets you had suggested but this would put my quench between .0405" and .0445". After talking to you I have found some Cometic .023" headgaskets on summit that would put my quench between .0355" and .0395". I talked to the machinist that decked my block and he thinks I am being too picky and should just run the the GM head gaskets and "call it a day". Usually when I succumb to this pressure I end up with something I am not happy about...
What do you think?
BTW, my compression is basically bang on 10:1 with the .023" headgaskets.
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