I've been trying do deal with this problem for years and have made several unsuccessful attempts to fix it. The oil pan leaks right around the rear main seal area. I have a post-86 gm block with the stock 1 piece rear main seal design. My leak however is not the rear main seal. The pan that I have been using is a Summit brand road race pan. I tried it with a felpro gasket and it leaked so I thought it must be the RMS so I changed that and it still leaked. Next I called Summit and they advised that I use their gasket, which was another wasted effort. I spoke to a couple people who said what I needed to do was put 4 spots of rtv in the corners of the block so I did that with another felpro perma dry gasket and it leaked. I thought "OK, it must be a problem with the oil pan itself so I'll pony up and by a name brand with a good reputation." So I spent $330 on a Canton road race oil pan. You guys want to know a secret? The $330 Canton pan is the exact same pan Summit sells for $230 that I already have on the car! Same metal, same design, welds in the exact same places even has "Made in USA" stamped in the exact same spot. Even has the same slight weeble-wobble when placed upside down on a flat surface. It goes flat if you apply decent force though.

So what do I do?
Ive heard people saying you have to use RTV on both sides of the gasket even though it's a FelPro perma dry plus one.
People talk about needing to use the rail reinforcement bars so the pan doesnt dimple but on a 383 I'd have to grind the sides in to where they would loose most of their strength.
Do I just use the new Canton pan even though it's the exact same one?
Do I pony up further and get an expensive, fabricated aluminum pan that will be dead flat and never dimple or warp?
I just want an engine that doesn't leak.
Gimme some thoughts and opinions please.

 

I always use a felpro one piece gasket and only RTV where the instructions say to. Honda Bond is my RTV of choice. no leaks ever even on my cheap chrome oil pan that came with the car. If you want to go all out honda bond both sides of the gasket and you should be good to go

 

Don't give up!
It's crazy how simple things can get so complicated to fix sometimes... sooooo much labor
TGO supports you

 

You have been absent for a while - good to hear from you.
Try this - I was told by a GM Master Mechanic (at least on Gen 1 blocks) that you need thread sealer on the 2 rearmost 5/16" oil pan bolts.
I hope it is as simple as this for you.

 

Feel like at this point it wont hurt to try a little rtv. I just did the pan gasket on my brothers 92 RS and used RTV on the 4 corners and across the rear main as instructed, no idea if it leaks or not yet