318 Two to four barrell advice

[thesado]

1.5 turns is a good starting point for the idle but you need to fine tune the idle screws once the motor is running.

I'm not sure how to do that.

installl a powervalve with at least a 2" lower rating

In the pri or sec? The pri already has one, but I didn't look which.

[Chryco Psycho]

primary only , I thought it had had a plug installed the way you described it .
basically turn in the screws until the rpm drops then turn them out until the rpm levels off & go maybe 1/4 turn out more