Initial timing settings

swies said

I have been scrubbing the posts trying to find some answers to timing.
I have an Eddy 1405 sitting on my Performer RMP AG sitting on my mild 1975 318.
The Carb has 2 vac ports on the base. One is 'Timed' and the other is 'Manifold'.
Which one should my advance can be attached to??? (Depends on what you want it for)
When setting the initial timing, should the vac advance be disconnected? Yes
I see in other posts that my initial should end up in the 8*-12* range and that SHOULD put my total at 36ish.
Does that all seem correct? or did I miss something crucial? That is about right for starters.
Thanks to all of you for the great help.

Click to expand...

A ton of reading up on Vac advance and why would be a good thing.
Manifold vac is in full advance at idle and ported is for zero advance at idle.
They are two completely different functions for different reasons.
Ported came about to make engines run hotter for emissions at lower/idle RPM's
Manifold gives full vac advance at idle and backs it down as engine load goes up via throttle plates opening and lessening the amount of available vacuum.

With a stock style distributor I think you'll find that setting it at 8-12 initial you will end up needing to limit the mechanical advance so you don't end up with way too much total between initial and mechanical (which is a normal thing to do)

I recently found a good writeup on it and I'll see if I can find it for you.

This one is a good one to start with.
http://www.hotrod.com/how-to/engine/mopp-0301-mopar-electronic-ignition-system/