so, just rebuilt and now my rear main seal is leaking....badly enough that it needs to be repaired. so what is the best seal to use? can I try to correct this leak while the motor remains in the car? I have to remove the transmission anyways so is it best I do it then? really frustrated with this motor. Any thoughts or direction is greatly appreciated.

Per some other's suggestions more than a decade ago I was able to roll a factory seal out and roll a new rope seal in with everything in the car. It was leaking bad enough that it would drip on the ground several times a minute. These days it doesn't leak any worse than the average big block. I probably got lucky.

I'm in the middle of trying one of 440 Source Viton rear main seal on a motor I'm having issues on sealing the rear main seal I haven't had one leak in a lot of years and now I've had several motors leak I may have a issue with the new batch of 10 rear main seals I bought earlier this year being bad
I'll know more tomorrow on if this is a good fix or not after running on the engine run stand, I'll post my results

This is the master "rear main seal" thread....

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1851379/1.html

The 400 Source brown Viton rear seals fixed my leak
I had used two other new black seals with no luck on this motor
I do use a sealer, Permatex adhesive sealant only, on the sides of the seal holder to seal the holder to the block on both sides towards the crankshaft flange and the bottom also by using a thin putty knife to try and force the sealer into the cracks between the block and seal holder bottom also
I change the seal holder also twice so I may have had multiple problems, not just the defective seals
IHTHs

Is that the low-deck division of 440 Source?



In addition to the "strips" or pipe cleaners, or just the sealant by itself?

When it comes to rear main leaks, I've had better luck using the newer CNC aluminum rear main seal retainers, over the OEM retainer.

Oops, it pays to proof read
For those that don't know, the seam size rear main seal fits all the B,RB and Gen 2 426 Hemi motors
I do use the side seals ALWAYS along with the sealant