vacuum - in general

[roadrage41]

got a wild hair and decided to try and get my timing a little closer to correct -
 
unhooked vac advance

 plugged vac gauge inline with just the port to the carb and the one that runs to the tranny connected
 
started truck, running about 11.5 idling in park (didnt have anyone to sit there with it in drive with the foot on the brake)
 turn clockwise, vac goes down to just under 11, truck starts to sputter. couldnt have been more than a few degrees clockwise that i turned it.
 
decide thats no good, start turning counter clock wise, hit 12, no pinging, hit 13, no pinging, hit 13.5, all the further i felt the need to go. still no pinging (not that i know what pinging is per se).

truck runs a million percent better, engine still starts when hot, most of the hesitation when you step on the gas is gone, had to turn the radio down a few times at stop lights because it runs so much smoother i thought it died.
i was reading somewheres that normal vacuum at idle should be like 14 or so with it in gear with the brake set, vacuum drops under load, yes? if its at 13.5 with no load im thinking i should go further, but i cant blow up the trusty 305 just yet.

should i go further ccw with it? i have no clue what pinging sounds like, is it going to be pretty obvious? lol when i bought the truck the distributor wasnt bolted down, so i knew it was off.

how much stuff should be running off of the vacuum line from the carb? ive got the distributor vac advance, the trans line, and 2 others that have something to do with the heater. but i have no other place to run another vacuum from on the carb that i can tell...

in short, should i attempt to go further ccw? is pinging pretty noticeable? and do i have too much crap on that one vacuum line?

\o/

russ

[Captkaos]

Is this a stock motor?  Is the numbers given the vacuum amount?
What is your initial timing set to?  I would set the timing at 10 degrees and start there, if it starts pinging you will hear it.  it will be a clacking noise.
Where is the vacuum hooked to now?  Once you get the timing set I would adjust the mixture screws for the highest vacuum amount.

[roadrage41]

manifold and carb are aftermarket, otherwise stock. those are the vacuum numbers. its a non esc distributor.

no idea, dont have a timing tab, or a light. just trying to get it closer "by ear" - have purchased the tab to install, just havent had the time... pathetic i know.

vacuum running off of the line on the carb, its a holley. should i mess with the mixture at this point since it is running better?

[VileZambonie]

Advance it til it pings and then retard it. Have the vacuum advance hooked up to manifold vacuum. Once you nail down the timing adjust the idle speed and idle mixture.

[Russ130]

If you're happy with the way it is running leave it alone for now. Having it slightly retarded is fine and in fact will increase mileage slightly. Vile and Capt are very skilled and I'm assuming since you are not sure what pinging is you are probably not. I would recommend putting the timing tab on and then getting a timing light before you make anymore adjustments to the timing or the carb.