I used the fel-pro that came w/my gasket set and slightly off set em w/a dab of silicone on the ends then install the sides dry. Then I fill the cavity on each side from top to bottom w/silicone on the outside of the retainer and let cure for a few days............

I covered in another thread on this issue, that I think seldom is the problem the crank OR the seal. It's the seal retainer. The retainer is just a cast and not precision machined piece. I have also seen some variance in the holes in the block for the retainer. If the bolts in any way, shape or form, pull the retainer to one side or cock it, you WILL have a leak and no seal or amount of silicone is going to fix it. The nicely machined aftermarket ones are great, provided the holes in the block are perfect.

During mockup, I always install crank, seal and then drop retainer on dry seal and seat it. Now look in the holes. If it looks like the bolt is going to influence the retainer in any direction, you WILL have a leak. So you try another retainer, or open the holes up. Now the next one I build may leak like a sieve, but I haven't had a big block rear main leak in years using this method. I also don't use the side seals, as they can push the retainer over. I use silicone. I also don't glue the seal in the block or cap. I put it in dry and clock the seal ends 90* from parting line on retainer

Chevy rear seals don't leak because the seal is contained in the rear cap and always properly located and clamped. The BBM seal arrangement looks like an after thought and often acts that way. Its the retainer

Monte, what kind of silicone do you use?

Usually Ultra-Black...........but if I am out, whatever I have........LOL!!!

Oil does not dissolve the RIGHT silicone. Cars come from the factory with silicone gaskets in some applications.

what about the billet rear main séal kit from Mancini or 440source are they good ?

All silicone, some just resist it more. If in contact with oil or gas it's neopreme

I haven't used a gasket on an oil pan, a rear seal retainer, on the china walls and several others places in years and years. I don't have leaks. You CAN'T have leaks on a motor and it make vacuum. And I have no problem with that. Our 738 Nitrous motor doesn't have a gasket in it other than heads, valve covers and intake. Makes 19" of vacuum and doesn't leak a drop. Your mileage may vary

I think some people are thinking silicone that is used to seal your house cracks. Were talking about automotive gasket adhesive or gasket maker.

I like the Orange 2 piece seals from Hughes or Mancini. I built 3 BB
Mopars last year with none of them leaking and no customer complaints. I like to line up the seals before the crank is installed. Once the parting lines on both the upper and lower seals are aligned, I scribe a reference line across the seal holder and oil pan rail. Keep in mind, there is play in that seal holder so if you install it without any alignment reference your new engine will leak.