I built a 261 in 2015. 59 block so neoprene rear seal and standard timing cover seal. Developed a leak in both. The timing seal leak turned out not to be the seal, but a failure of the timing cover gasket. I always modify the front main cap of all of my motors so that was easy to fix. Shortly thereafter, the rear main started to leak. It was leaking like a sieve and I was in no mood to tear it down. So I gave the Barr's a try. Stopped the rear main seal leak so I am not surprised that it affected the front seal of your motor. As for the rope seal on your block, the Barr's specifically states that does not work on rope seals. So the Titan would be my next stop although I don't see where it is useful for rope seals but maybe I just missed it. Also, the Barrs did not thicken my oil. It supposedly works by swelling the seal, not by thickening the oil.

I won't lie, I was as surprised as anyone that it did the trick but it did do the trick.

Mike