Ok I have a 1983 gt ho rebuilt motor only about 5,000 on it flat tops and a mild cam. What should total timeing and base timeing be,m i have been trying a few diff combose but though i would ask so other people. also do you run manifold vac advance or do you run ported vac. or none at all and increase your base timeing. I need a good set up for good over all perf.

Thanks guys


BigMg

 

Mitch, remember when we did the timing on the old Chev and put it to full vacuum? You want that so that you do advance at idle for a more smoother idle and what not. Your mechanical weights and springs should be where you should look at when you want full throttle hi perf action since there's no vacuum at WOT. Leave it on vacuum for cruising and gas mileage. Have you tried anything with your weights and springs? I'd say total advance should be around the 34-36 mark.

 

soppa if you have full manifold vac at idle you will have the base timeing plus full vac advance witch would then be 13 plus lets say 20 deg. that puts you at 33 deg at idle i don't think that is right. With port vac you will have the base of 13 at idlea with no vac advance , that will increas with throttle

 

MItch, you can afford to have extremely advanced timing at idle because the car's not under a load. Once you open the throttle and put her under a load, the vacuum advance will drop off a bit.