+1 on removing the engine if the rear scroll has been machined off and a lip seal fitted and it's leaking.
Willie I don't know if you fitted the seal but they don't normally give too much trouble as long as fitted well. Conversely it's quite possible to STILL have the rear mains leaking even with a well fitted crankshaft seal if the engine has breathing problems. I would check it and confirm that isn't the case, try running with rocker cover filler cap not fitted and look for emissions, select Forums and try a search in the search box under engine breathing and go through some of the remedies there before attacking the engine.*
* I just did this and got 148 results, some may not be pertinent but I'd be surprised if 50 threads don't tell you how to bottom engine compression if you haven't done it already.
Edited by Motorsport Mickey, 15 May 2018 - 12:14 AM.