ok so i got we put a new rebuilt 350 in my 80z and were having trubbles setting the ignition timing. we use a gun with a timing advance and i set it to 6 degrees advance then set the pully thing to 0 but when i turned the adv dial back to 0 on the gun, it showed it as like 14 or 16 degrees BTDC. any ideas? should i base my timing off the light advance or the actual marks on the engine? its a 3970010 block and the other code i can only read a 42, the rest is gone for w.e reason. the timing light is a cen tech part #40963. plz help

 

I've heard/read about numerous guys having accuracy issues with their dial-back timing lights.
I don't have or need one, the old standard fixed light is just fine with me.

 

I also use fixed std. light, and set it by the crank harmonic balancer and tab. Be ure you've got the vacuum line off the distributor and plug the end that goes to the engine while setting timing.