1st get the reusable gasket best gasket you will ever buy 2nd if installed correctly no gasket needs any sealer at all we use the fiber gaskets at work I use no sealer and have no problems.

70 duster full chassis super pro 416 CNC Indybrock heads 727 w/brake

best so far 1.212 60 6.219 in 1/8 at 110.88 9.768 at 137.81 1/4