I have a 1960 261 that had the front of the crank knurled - I luckily found out last year that this had been done because the balancer hole was a little wallowed out.
We put on a different balancer - it was good and tight.
We had already drilled the snout of the crankshaft (using Hotrod Lincoln's loaner drilling jig - thank again, Jerry) - this is a nice "insurance-policy".
