just passing this experience I had

I was installing a 1 inch fomoco spacer

when I change the carb studs on the air intake I found oil and gasoline inside the threads I read that you could have leaks thru there but not that big

I put teflon tape on the new longer studs that I made

when I checked the vaccum tester the needle was steady at 21

I really recommend all of you guys to check and seal those studs IMO

In my case it gave me a sweet idle on my 302

 

FYI: you can't use the ford spacer on aftermarket intakes.