RIGHT STUFF works good for some things. Example is the dipstick adapter where the engine oil dipstick goes out of the right side of the oil pan on an IH 7.3L PowerStroke engine. The o-ring inside the pan that is supposed to seal the adapter grows in the hot engine oil and gets out of the groove. You can replace it if you have 5 arms but risk dropping the adapter inside the oil pan which requires engine removal to remove. I used RTV to seal up the outside of the adapter the first time, lasted about a month, used Right Stuff the second time lasted FIVE YEARS.
DO NOT USE RTV WITH GASOLINE. It turns to jelly are grows in volume. I used white bathtub chalk to seal a thermostat housing on a Farmall once. Lasted about a year. Best way to seal ANYTHING is buy the OEM paper or composite gasket and swipe a thin layer of HYLOMAR ULTRA BLUE UNIVERSAL GASKET SEALANT on it. Forget buying it at NAPA, get it off Amazon. I've had terrible luck with Permatex #1, #2, it may be the right sealant for some things but I haven't found anything it works on. Oh, and anything you get a CORK GASKET to use to seal up, THROW IT AWAY, use the RIGHT STUFF instead. On the high volume applications like Chevy small block or Ford small block valve covers they make rubber coated steel laminate gaskets that are life-time parts and don't leak, act like an o-ring for complex shaped parts. IH used some on their truck engines but nothing on a FARMALL. Hate cork gaskets, what made people think decaying tree bark might be a good gasket material? IF you can get a cork composite gasket, small particles of cork molded into a rubber or butyl rubber gasket material they are fine. Straight cork is brittle, it compresses, takes a set, then shrinks and leaks.