ok i just set the timing rgt 18deg at 700 rpm and 35 degs all in at 2500. ok so how can i set my carb to run better? bc the car just dont feel really that fast ---------- what color spring should i use in the vac secs

the secondary spring is determined by how much vacuum the engine produces...

35* mech advance?
18+35= 53*
or 17* mech advance...


if your at 35* mech advance plus the 18 base i wouldnt run the vacuum advance are you?

you might get better help in the carb board for tuning help

No kidding. No offense, but everything you said was wrong.

Vacuum is used to determine the power valve, not the secondary diaphragm spring. Basically, start with a "heavy" spring, test successively lighter springs until you feel the secondaries opening (aka - "bog"), then go back one heavier spring.

18 initial with 35 total means there is 17 degrees mechanical advance. You definitely need vacuum advance on top of that for street driving. If it starts and idles okay, then you probably don't have an issue there. 36 is typical for SBC's, though. One degree probably won't make much of a difference.

Need to know more details about your engine, tranny, gears, etc., to say much more.

good point... carbs are new to me i thought you could choose a spring based on the engine vacuum at idle...

and i was trying to figure out if he meant 17* mechanical or 35*

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