350 engine idle shake HELP!

[Awann99]

I’ve had the truck sitting for about 3 weeks while I redid the door rubber and now when I start it, the engine shakes vigorously. It ran perfect before I let it sit. I’ve checked and rechecked the wires and they are all going to the same spot. I’ve moved the distributor clockwise and counterclockwise to see if the timing was off but it stays rough no mater how far I turn it each way. I put my hand over the top of the carb and it seemed to slow the shaking. I think it may be a vacc leak. How would I check for a vacuum leak? It did this once before and I took off the rotor cap and filed all the buildup off of the points about a 2 months ago. That helped but I don’t see how so much buildup could occur that quick if that is the problem again. .
350 abc crate engine. 3 years old. Edelbrock performer intake, HEI, and stock q-jet.