What do I time this 425 to 65 js1

 

5-7.5* BTDC @850 rpm with a 30* dwell. Idle rpm is 550 in drive.

 

Keep in mind that the factory timing spec assumes a nearly new engine (ie, no carbon buildup in the cylinders) at stock compression ratio using the gasoline available in 1965. Modern gas and any changes to the engine (including carbon buildup from age) will alter the optimum timing.

 

I tell everyone to give a normal street-driven stock-ish engine as much timing as it will tolerate without preignition.
Big variables are the fuel octane, ambient conditions(seal level & temp), condition of the ignition system, and your driving habits.

Check your engine for vacuum leaks before adjusting anything.

Adjust the timing and A/F ratio with a vacuum gauge, (highest vac reading at curb idle) then verify with a timing light. Road test/repeat.

Check the vac advance canister and centrifugal advance mechanisms for proper function and lubrication. Same for the point set. (lube the bumper).
Check the distributor shaft for side to side play(slight up/down play is normal).

Want "super tune" info just ask.