84 has a vacuum advance 89 has an electronic advance Thats the only diff.
The vacuum canister can advance 24 degrees beyond initial timing.
California emmissions full,49 states part
around 6-8 degrees with the vacuum advance blocked off. electronic ignition has no vacuum advance! How does one blank off the electronic advance???
Yes, The vacuum advance advances the timing to help on acceleration and also will increase gas mileage.
Look on the carb for a small vacuum source above the throttle body. You would want one that has no vacuum at idle.
6 to 8 degrees BTDC / Before top dead center. with vacuum advance pluged.
how do you adjust the timing on a 1977 350 Chevy engine k-10
That engine does not have a vacuum advance.
check for vacuum leaks
That should be a 350 cubic inch engine with a carburator, HEI ignition with a vacuum advance. You will need to hook up a timing light to number one (1) cylinder. That is the front plug on the driver's side. Start the engine and let it warm up. There is an indicator on the front lower side of the engine. It is marked with the degrees. Disconnect the vacuum from the advance and plug it off and then adjust the timing to the desired specs. Tighten the distributor and plug in the advance. If you do not get an increase in rpm when the vacuum is connected, then the vacuum advance is bad.
You will need a timing light with the timing advance option so you can adjust and monitor your changes. Vacuum advance limiters along with mechanical advance timing weights and spring kits are available from after market suppliers.