Here’s what I did:
Stock J-code 302 engine.
(1) Threw away the cork gaskets that go on the end “china walls” and used Ultra-black instead (applied liberally).
(2) Used bolts (with heads removed) at opposite corners to line up the intake manifold for a “first time correct” installation.
(3) Cleaned all mating surfaces. Cleaned them again. Put paper or towels down in the lifter valley when cleaning the head surfaces so that dirt, etc doesn’t get into lifter bores, etc.
(4) Put a *very light* skin of RTV just around the coolant ports, both on the heads and on gasket toward the intake… just enough to fill any slight imperfections/scratches in the heads/intake that might be there.
(5) I aligned and then installed the gaskets on the heads using Permatex high-tack gasket sealer to hold them in place so they would not shift when the manifold is laid down on them.
Per a comment above: “Also, make very sure that you are using the correct gaskets for the intake. The main difference between the early and late versions is the size of the coolant ports. If you use the wrong one, you will develop a coolant leak at the corner...”
++1 on that comment. I originally bought the higher price Fel-Pro gasket (thinking expensive = better) which was made for any generic 302 engine compatible with different heads, some which have larger coolant ports. Because it allowed for larger coolant ports, there was less gasket material between the port and the corner of head. It leaked so I had to remove it and do it again… &#@(!*&&%. Second time I bought the Fel-Pro print-o-seal gasket that had the same sized coolant ports as my particular set of stock heads. Installed it exactly the same way I had the first set of gaskets. Worked perfectly.
One other suggestion. Once you’ve got the intake installed and let any RTV set up, pressure check the cooling system (eg mine is spec’ed for 13psi) and check for leaks *before* you reinstall everything else. This will save you some time. On the first gasket I put on, it started leaking at ~10psi. Second gasket was tested up to ~15psi (don’t push it any higher than than) and held pressure fine (15min was how long I checked for). Had I just re-installed everything, started the engine everything would have looked fine (even with the original “leaky” gasket). Only sometime in the future, on a hot day, when the psi > 10 would I have found the leak.
Also, here Youtube is your friend. If I recall correctly, there were some good intake installation videos from channels: