Drill the holes. but make sure you put a piece of wood between the timing cover and bracket being drilled. It would be a waste of time if you put a hole in the timing cover with a runaway drill bit. Then you will need a timing cover to boot. I did this exact thing in my 51 Chevy 2 dr sdn. when I put my 261 in a few years ago It worked fine. no locating shims but it didn't matter. Mounts still stay put. Well till you rip em apart like I did...lol... After the fact I ended up chaining the motor down. Didn't want a repeat. If I had todo it again, I would, except I would drill alitta bit more on the wide side than I did.
