Another thing to consider. As you can see, Chevy had an odd way of retaining the timing cover to the block. Mostly screws, although sometimes bolts, from the outside, but two bolts and a retainer from the crankside side of the motor. I have no clue why they would do it that way, maybe a sale on pan gaskets or something. What this means, is if the timing cover leaks you have to pull the pan to get to those two bolts in order to replace the gasket.
A really old modification, tap the front main cap for threads, i forget offhand what size they are, 3/8-18 maybe but not certain at the moment (the holes in the cap are close enough to the correct drill tap size to do it), and drill out the timing cover and plate to oversize, so that you can install all of the bolts from the outside. I have done this to a majority of the motors I have built. Had a timing cover gasket fail just once, with the most recent 261 build. Boy, was I happy. Only had to deal with the front of the motor, and did not have to pull the pan to do it.
