timing question

[silver 80]

The ZZ4 is in I didn't have to remove the dist. so it should be timed right? Carb rebuit new gasket (Q-jet). I'm geting back fire somtimes.
Starts easy when it's warmed up, takes a little bit when cold.
vacuum leak? I checked the timing with the vacuum advance off and pluged and it wasn't at 12 like i thought it should be.
I guess i should get it there first and see what happens.
does this sound like good plan.
I could throw on the crate demon and see what happens.
tom

 

[JohnZ]

Verify the timing first - it probably came set just so it would run. Check timing at slow idle (vac disconnected), then rev it up gradually until it stops advancing, and read again (that's "total timing"); the difference between the two is how much the centrifugal advance in the distributor is adding. Most SB's like 34-36 degrees total, with 20-24 degrees in the distributor, all in by 3000 rpm, which would put your base idle timing at around 10-12 degrees. After locking it down at 34 degrees total timing, re-connect the vacuum advance and re-set idle rpm where you want it (speed screw) and idle mixture (mixture screws) to the highest manifold vacuum reading. That will get you a baseline setting to work from.

 

[silver 80]

Thanks John