Large rpm drop

Mattax said
View attachment 1715457944
I would not touch the distributor springs at this point. There's no vacuum advance, right? If there is, don't use it for now. Once the idle in D is better - assuming it is better - then do some gentle accelerations from idle.
If there is no hesitation and that works well, try a gentle uphill.

The only reason to mess with the springs at idle will be if the timing is not stabile at the idle rpms. In other words if the timing in P or N is 18* at 800 rpm and in gear it is 16* at 700 rpm, then increasing the spring tension on the light spring will solve that.

Of course, only touch springs if obviously needed.

I also have a Fast E6 ignition box and a dial timing retard unit under my dash, so I can set the distributor and dial back timing while I'm in the car. Then check to see where it's at, dial back to zero, clock distributor to match and go from there. Experimenting with timing is no big deal so I'll see what works best. Thanks for all the input!