Stop leak in my day, you put a piece of cardboard over the radiator and got the motor much hotter than it would ever get to normally. Then let motor cool. If the motor get any hotter than when you used it it will expand more and blow out the sealer. With that said IMO you need to find and fix not use a band aid. Good luck. Also did you buy the intake new or did it come with engine when you bought it?
What pressure cap are you running on the radiator? Are the factory roll pins removed from the blocks front and rear China Walls? Are you using end gaskets on the block?
