Dalba4 gives good advice, it will give the best results. But there is a matter of economy involved. If you go downtown and buy all of those products in a new can, you'll spend some bucks some might consider is excessive. .
The gasket problem isn't very complex. Clean all the surfaces with a good paint reducer to get clean metal, use high temp RTV to lightly circle all the ports. Toss the new rubber end gaskets and use RTV and build a dam of RTV on each end, squish it down by bolting down intake.