318 vs 360 weight

I think I remember reading that 360s are actually 25-50 lbs. heavier than 318s, from the external balancing and different main bearing sizes... could be wrong though. IMO factory T-bars were barely adequate for 1960s tires, and are way obsolete for even the simplest modern radial tires. I'd strongly recommend big-block-size or bigger torsion bars in any V8 car unless it was set up for strip action only. Of course if it's all you have you should be OK, just don't take corners too sharply (as I'm sure you already know).