I do it for all my motors. Case in point, a couple of years ago I had a bad leak at the front of my 261. I assumed it was the seal. Turns out it was the timing cover gasket. Because I had done the modification, I did not have to remove the pan to remove the timing cover.
Keep in mind the reason for the bolts through from the inside had to do with in chassis maintenance on earlier motors. When the crank and bearings wore out a bit and the clearance because excessive, you did an in-chassis maintenance and removed shims or replaced bearings. So you could pull the pan, remove the lower timing cover bolts, remove the front main cap and do the service without having to tear down the front of the motor.
Not really a thing after 56 and the introduction of precision bearings. No adjustment for those bearings.
I will also say that in addition to modifying the timing cover for outside bolts, I always drill the snout of all my cranks for a balancer bolt. Keeps the balancer in place god forbit it gets even a little loose and starts working itself on the cranks snout ruining the snout and the balancer, but also because it makes installing the crank gear and balancer, and removing the balancer soooooo much easier and less chance for damaging the crank thrust bearing when installing the balancer with the block of wood and hammer method.
These days, its more likely that I am messing with these old motors by myself so finding someone to hold a pinch bar against the crank while I hammer is not as easy as it once was.
Last edited by Dragsix; 07/11/2025 4:34 PM.
