Quote:
Originally Posted by dhcarguy
Thanks, I will check them this winter
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The size of the idle bypass restrictors are critical if an aftermarket cam is installed. The stock Tri-Power center carbs have them at .043" or .046". I've found that with a cam similar to the RAIV cam, .052" is a good starting point. Some more radical cams require .059" or larger.
The idle tubes in stock Tri-Power center carbs are usually .032"-.035". For a cam similar to the RAIV, the tubes need to be .038"-.040". With more radical cams, the tubes need to be .040"-.043".
The idle vents above the brass tubes should be about .040"
The throttle base idle screw holes are usually .070". I usually enlarge them to .078" so the screws can be adjusted further in with the same flow allowed.
Most stock end carbs have .066" or .068" jets. With a mild cam, I put .070" jets in the end carbs. Any cam similar to or beyond a RAIV, .073" jets.
Center carbs, whether pre-'66 or '66, begin with .063" jets. With a more radical cam, you may need .064" or .065" jets.
I've found that cutting five turns off the power valve rod spring will suffice for most aftermarket cams.
Unless you do the above, your engine will not idle or perform well with an aftermarket cam.