Lots of replies thanks guys... so first off, this rough idle issue was there even with the stock 2-bbl Holley which I rebuilt and cleaned before doing the 4-bbl conversion and it did nothing. This Edelbrock was used and had sat for some time so I went through it before putting it on the truck, it was in better shape than I expected. The truck also never sits more than 3 weeks or so and I usually add either Lucas ethanol fuel additive or occasionally fill up with ethanol-free gas. I'm not ruling out the carb but there are other places I'd rather look into first.
I'm going to try plugging off the brake booster vacuum port and spray water around the carb/ intake area to check for leaks this evening.
@George Jets if I had a cam lobe going bad wouldn't it be making noise? I didn't inspect them closely but when I had the intake off I looked over all the cam lobes and they all looked normal and consistent.
I'm thinking of also testing the electrical stuff, particularly the voltage at the coil when running I feel like there might be something funky going on there. This problem has existed since I first got the truck running with all the original parts and there are still some weird minor electrical gremlins I need to figure out.
