how to seal coolant leak

I had a very similar issue years ago with a 302 block with 289 heads in a '66 Coupe. I added an Edelbrock alum. intake and had found coolant in the oil. I tried 3 times with 289 intake gaskets and once with the 302 intake gaskets to no avail. I ended up putting the OEM 4bbl intake back on. Problem resolved. To this day I don't know what was causing it.

It irritated the crap out of me. I don't know if this really helps but I thought I'd throw it out there. Maybe someone that has conqered this
issue will chime in.

Good Luck, GT

I have Permatex RTV gasket maker between the aluminum intake and the block. It works fine, so maybe he is on to something.

if you have installed an aluminum intake, the issue might be at the coolant transfer ports. here is how i install aluminum intakes on small block fords, and i have yet to have a leak;

first i pitch the cork end gaskets
i put a thin coat of rtv on both sides of the coolant ports on the intake gasket
once the gaskets are in place, i run a bead of rtv where the cork gaskets go
i gently put the intake in place, and verify that the gaskets have not moved during the install
when i torque the bolts down, i start by torquing the corners in a criss cross pattern to 25ft/lbs, and then work inside out in the stock ford pattern. i then go back over the bolts torquing them to 30ft/lbs again starting with the corners, and then going to the stock ford pattern.