what main seal retainer did you use, and how did you seal it to the block ?
did you open the retainer bolt holes to allow the seal to find it's happy spot to seal ?

The original

SOOOOOOOO, Nobody has replaced a rope seal in the vehicle?

Im going to try it, Ive got nothing but time, and Im fairly patient...

I tried long time ago, not going to happen. I said a while back, seal has to be seated in the block with a special saddle tool, then the ends have to be trimmed. Look it up in a factory manual.

Ive looked that up before, Ive heard of several doing it with success, I guess Ill give it a shot, im a tech by trade, worst case is I have to pull it out and do it. Engine could use a paint job, and a set of 440 source heads.... LOL

Is the seal surface on the crank knurled?

I put one in on an engine stand (400 olds) the proper way, too. Which requires clamping and trimming. At the end I could not accept the required turing torque with the finished product. Ripped it out and put in a modern replacement style and will never waste my time on a rope again.

I can't imagine doing this in a car. The crank has to come out.

I'll be the first to bet you will end up doing it with a replacement seal.

I have made that mistake once of replacing the early stock rope seal with the motor in the car, never again
Mopar and probably others had a special tool for that, the bad part was you had to loosen or and remove most of the main caps which let the crankshaft weight hang on the timing chain while doing that job, not good

Same here. I have never had a rear main leak.

Since I said that, mine will probably leak the first pass this weekend......

Same here, put it together than let it sit for a day to dry the sealers.

Nick just fixed a 383 that leaked like a screen door on a submarine

I had not either until recently. I had purchased 6 or 7 rear main seals during covid as I had three engines going together and always something in the works. Well my 64 had a small leak from the rear main, not a huge deal but I HATE leaks. I did not build the engine in the car originally. So I pulled it apart to look it over and fix the leak. Going back together I used one of the seals I bought in 2020. Put it back together as I always do nothing different. It went from a small leak to a gusher!!! Driving it around the block I saw it loose all pan vacuum and by the time I hit my driveway I was leaving a trail. The seal I pulled out of it was the same color and likely brand as I used. So I ordered a new seal from another manufacturer and no issues. So looks like I will throw away the remaining seals from 2020 as that is the secind one that leaked. My Predator had a small leak as well after being on the dyno and a few passes on it.