I have tried the method of using some tubing to find my vacuum leak (help hear spots around engine)

I think I used some sorta spray too once before. This car is rarely driven. Im needing to get it inspected and ready for the road. The RPMS climb up like crazy while in DRIVE (gear)

1. How can I find this leak?
2. Best place to buy gaskets etc?

I have an 84 Z28 with the 305 and a auto (carb)

brake clean, starting fluid, propane torch

you may get luck and just have to tighten down the intake