The rear axle is a GM, 12-bolt and, to be sure of the gear ratio, pull the pumpking cover, count the teeth on the ring gear and the teeth on the pinion gear...divide the larger number by the smaller number and determine the ratio. That is the only way, to determine, for sure, what the ratio is, since it could have been changed at some point. Also, popping the rear cover, is a good time to inspect and grease the rear with new 90 wt. rear-end lube and install a new pumpkin cover gasket. You may also find out if you have a posi, by doing this exercise.
The motor mount is home-made. The two holes in the front of the engine at that location, are for the power steering pump mounting brackets. The exhaust manifolds are not factory-correct, nor compatible with the factory-correct motor perches, whereas the factory perches have been removed. You can see the visual evidence of their previous location. The factory-correct exhaust manifolds for the 283 or 327 V8 motors, were the center-dump Rams Horn style, cast iron exhaust manifolds.