Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

What rods/jets needed to dial this in?

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EspriTA350:

--- Quote from: Cliff Ruggles on May 09, 2020, 02:50:43 AM ---Quench needs to be tight, especially in a Pontiac build with iron heads.  I would NOT build one with more than .040" quench distance for any reason........FWIW....

--- End quote ---
That's one thing I'm not sure about. I know the heads have at least .020 milled so that should improve the quench some, correct? I am using run of the mill fel-pro 8518pt head gaskets and cannot find anything other than speculation on what the actual compressed-thickness of these gaskets are. I would prefer cometics with their tighter bore and all, but getting my engine machined for the proper RA finish is just not an option for me (and won't be for awhile).

tayto:
bring piston to TDC (use dial indicator), measure from top of deck to top of piston. then add your compressed headgasket thickness to this and you have your quench measurement.

You can adjust quench with headgasket thickness or getting deck milled. the popular thing in the SBC circles is to "zero deck". machinist will mill deck so it is exactly @ top of piston, then the headgasket strictly sets your quench.

Cliff Ruggles:
The Felpro head gaskets compress at .039-.040".  This works out well if the block is zero decked or pistons sticking out a few thou at TDC.

You'd be surprised how much better that deal works out than having the pistons .030-.035" in the holes at TDC and using a .050-.060" "rebuilder" head gasket on them.

I see the latter all the time, and it's rare to even talk to a customer wanting parts or carb work that has the first clue as to what the quench distance or true static compression ratio is on his new engine build........FWIW.....

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