[jketron]

I have a crate ZZ454 and a GM HEI distributor that was recommended for the crate (its new)

I have the total timing at

36 degree at 3500 RPM
its 21 degree at idle with vacuum port to full manifold 630-650 RPM

The initial timing is 0-1 degree and barely runs

Does all this sound right, do I need to make any changes or get something re-curved?

 

[jketron]

Used timing light with rpm and adv/retard dial to determine rpm and actual timing

 

[mr 4 speed]

set it for 36* total with the vacuum advance disconnected.

 

[jketron]

If I do this how will this be setting total timing? I wont be accounting for the 20 degrees the vacuum advance unit is providing

 

[Jerry70]

If I do this how will this be setting total timing? I wont be accounting for the 20 degrees the vacuum advance unit is providing

The term "total timing" refers to initial + mechanical and does not include vacuum advance. Typically, at light load with mechanical all in AND vacuum advance all in you'll see around 50º of advance. You may need change your canister as 20º may be too much for todays gas.

 

[jketron]

Im working under the impression that total timing of 35-36 takes into account vacuum too, is this not the case?

 

[pauls72]

No that's not the case

 

[mr 4 speed]

set as I said and you will be good to go...with 8.75 thru 9.1 compression and 93 octane you should have no worries
It will be a whole different car

 

[jketron]

Thanks folks, I did it as you said and it runs fine. Thank you for the lesson.

Now I can't wait for my new motor being built