Need help tuning a 273.

trebor75 said
Yesterday I warmed up the motor. Plugged all vacum ports on the carb and set the timing to aprox 12 BTDC. The motor idles at about 500rpm. Is that a little low maybe?

I then attached the vacum hose from the distibuter to the higher of the two ports on the carb like you suggested "Fishthatkills". I could only feel vacum in that port when I reved the engine.

It runs much better now, there is still some hesitation if you stomp it from start though.
I dont know the total timing either, the scale runs out, so How do I set it?
A friend checked with the timing gun when I reved the enginge and it stopped climbing around 3000 rpm but it is just a guessing game where it was.

So your timing is set to basic now.

Need to put a vacuum guage on either the base carb vaccum line (usually to PCV valve, or off the intake vaccume tree. Then and adjust the Idle to about 650-700 if manual trans. Not sure which carb you have, but if its the old Carter, you adjust center Idle Air screw to best vacuuum, then the two idle mixture screws, then re-verify center screw and lastly re-verify the 2 mixture screws.

Once set, then test drive to check again for the hesitation. If still there, move back to the timing. Add a couple degrees and check again. If worse, reduce a couple degrees and check again. Continue till it moves and takes off like you want, OR until you get best response.

If you get to a point where you ping, then you're definitely too far advanced.