Sorry...had to take care of "stuff" here. There's a good answer above, Kevin. This may be like the question regarding the 3M 08509 windshield sealer. The 3M product was great and the CR Laurence product is okay. Some folks on other forums (particularly paint/body shop forums) have been very explicit on what they think of the CRL stuff, but I won't repeat it here.
Please understand I've used the Permatex Aviation sealer since at least 1978 and there is nothing wrong with it. It will work very well...as long as you take time to get to know that product and what it can and will do. In some cases I consider it better. In fact I just used it to seal the front plate and camshaft gear cover on a 235. I have also sealed differential covers this same way with great success.
Here is what I've learned...it performs differently. I took the gaskets outside in the hot sun, painted them with the sealer (first one side and then later turned them over and did the other), let them sit on a piece of cardboard in the sun for about an hour. Repeat if needed. If you do this, you'll see the gaskets (fiber type only...not cork) become completely saturated and will be sticky. The front plate of the 235 as you might know needs to be sealed really well or over time it will leak. Vibration, movement, oil from the cam gear oiler channel, etc isn't a friend and there aren't quite enough screws securing it (in my opinion). Sealed in this fashion I've learned it will not leak for decades. Same with a differential cover. Those things (especially if you live down here) will dribble unless you get them sealed just right. Soak fiber gaskets all the way through and your rear end will be tight and dry.
What I've learned about the Super 300 is that if you use it on something like a side valve lifter cover you can remove it by letting the engine get to operating temperature, removing the screws and gently working it away from the block. Then you can usually clean the gasket well with acetone or lacquer thinner and re-use it.
