Experimenting between manifold and ported vacuum
I have a '69 Malibu with an '84 GMC 461, stock compression, Isky 270 cam, high rise intake, headers, 3" exhaust, stock converter, 2.73 open, and GM HEI.
I just put an Edelbrock 650 cfm Thunder AVS on the car and love it. However, the guy I put it on with hooked the distributor to manifold vacuum. It works great, but Edelbrock recommends using ported vacuum.
I've read a ton of posts about ported vs. manifold vacuum and it seems to come down to personal preference and individual engines. I'm going to experiment and would like to compare apples-to-apples. Beside switching the vacuum line, is there anything else to adjust when trying out each vacuum port? I assume I'm going to have to adjust the mixture and idle screws. Anything else to play with to get a level field of comparison?