Need some timing advise...

Put some new topend parts on the 390 the other day (head gaskets,intake carb ect). Now I can't seem to get the timing right?
It is slow to start up, then once running, the valve train is clattering on hard acceleration. What are you guys running for timing? Motor is very mild.
Thanks,
Graham

 

I set my initial timing at 14, but there is no air up here. Factory manual says 8. Something sounds pretty messed up if the valve train is clattering. Are you sure your not hearing pinging or a timing retard surge?

 

I think the timing is too fast or the vacuum advance is hooked to the wrong port. Make certain the port it is attached to has no vacuum at idle. The initial timing could be too fast causing slow starting as well.

 

Its sort of a deisel sound @ the bottom end? Timing is either too late,or too early? I'll try those #'s when I get home.
Thanks

 

Hook the vacuum up to manifold vacuum. It improves idle quality and fuel economy. On hard acceleration you dont have any manifold vacuum which should bring the timing back to where it shouldn't clatter. Keep retarding it until the clattering stops.

 

The vacuum advance is hooked to the outlet on the metering block on a holley vacuum secondary. Which is where Holley recomends I believe.