Hard starts after running

Mattax said
I see. Well for any downdraft carb it is important to keep the transfer slots in the range they will contribute the correct amount of fuel and air at idle. The method sugested by A/J will put it ballpark correct on any standard older 4150/60.
A search should turn up evidence this is not something A/J pulled out of thin air.
eg
https://www.forabodiesonly.com/mopa...-duster-backfire-issue.545100/post-1974388877
When transfer slots are out of range, then it is possible for idle to be OK, off-idle will have dead spot or delayed response.
Based on Holley's recommendations printed in Urich & Fisher's book.

I didn't know what I didn't know. It makes more sense, setting the transfer slot and adjusting the initial to bring the rpm into line. Instead of using the idle screw to account for a timing number.

following the procedure outlined by AJ, I just pulled 5 degrees initial out, from 19 to 14. The engine is more responsive despite the decrease in timing. I will need to add s few degrees of mechanical back in the distributor. Not a big deal.