[Formulajones]

Most of these 60 year old cranks have so many miles on them already running a rope seal for decades that they are already somewhat polished up. That's been my findings anyway.

I put viton Seals on every Pontiac I build stock or aftermarket crank and just to be safe I still have the factory cranks polished up on the seal area to remove any sharpness they may have. I've never had a leaker.
I haven't seen serrations on any aftermarket cranks Ive dealt with but that doesn't mean they all dont.

[Sirrotica]

The serrations are angled so that they tend to pull oil back into the crankcase as the shaft is turning. If they serrations were there to keep a seal from glazing they'd, be straight cut.

Pontiac isn't the only manufacturer to use serrations, some older engines used rope seals both front, and rear, many have serrations. All the ones I have seen are angled so that oil is pushed inward towards the sump.

The problem with rope seals are originally they were used on low speed shafts, and the packing could be tightened with a gland nut (think faucet packing), or collar to allow for wear. In an engine application there is no way to adjust tension to allow for wear, it's also being used on a high speed shaft. Obviously a less than desirable situation. It's going to leak eventually, lots of things will affect how long before a rope seal starts to leak, crankcase pressure etc.

I worked in a GM dealership when the 5.7 olds diesels were still under warranty, (mid 80s) also used a rope seal. If the rings were worn, or the PCV system was neglected, there was no way whatsoever that you were going to seal one of those engines. The rope seals don't hold pressure well, and they barely are able to hold oil back when everything is right. Add a compression ratio of 22 to 1, and you have instant crankcase pressure.

There are better engineered seals now, but 50 years ago rope was one of the common seal types used in many engines. Getting a rope seal to be oil tight is, much luck, and voodoo, there's not really any science, or skill involved. No matter how much care I used installing rope seals, you get leakers right from the get go.

As far as lipped seal being used on a Pontiac shaft, I would want the serrations polished level with the rest of the shaft. Machining the main bearing journals has nothing to do with the seal surface, as it's rearward of the main bearing surface on it's own journal, behind the slinger..