The Best Gasket seal is the closest thing to the ones we were using back in the 1950's and 60's. It's not identical, due to the elimination of asbestos in the rope, but it's pretty close. I usually soaked rope seals in clean 30 weight oil, then packed them as snugly as possible into the groove in the block and the cap. OTC used to make a seal installation kit that included a "Chinese handcuff" puller to coax the upper seal into place and a shield to avoid scoring the crankshaft as the rope was cut off flush with the block. If any seal material is left protruding above the cap after packing it into place, make it VERY short, like 1/32" or less. Best recommends putting a 1/16" roll pin into a hole drilled in the cap to prevent seal rotation, but I'm nor entirely sure that's necessary if the seal is installed right. It was not done that way back when these engines were daily drivers.
I'm working on a machining fixture to allow the back of the block and the main bearing cap to be machined for a full circle lip seal that will eliminate the rope seal altogether. Once that's finished I plan to write a tech tip on the procedure. It involves using a cylinder boring bar instead of requiring lots of setup time on a Bridgeport mill. If it works the way I expect, the job should require less than an hour working on a bare block during a rebuild. The picture thread from the homecoming shows the fixture setup, but I didn't have a main cap available to complete the demonstration.
Jerry
