A 305 isn't a bad motor really. From what I recall, basically a 2 bolt main bearing 350 with a few less cubes. Its still a small block GM motor, so almost all the same aftermarket HP stuff fits, just not as much cubic inches to get power out of. You can build the hell out of a 265 V8 with much of the same stuff you'd bolt to a built 350. As always, free is an excellent price, and once it is in you'll be able to use all the same mounts to drop a 350 or 400 in there when you fall into a free one of those.
Powerglide trannies are pretty hardy too, my dad had a 66 El Camino with one. It leaked fluid like a sieve, but never stopped running. Last time I started it up, it had been sitting for 3-4 years, just topped off the ATF and drove it right out of the holes the tires had sunk into. Nicest thing about it was it was rear pump so you could actually push start the car even with an auto trans. Came in handy on one occasion I can remember. Two speeds kinda sucks for highway use, but for mainly offroad its not that bad.
I bet the 305/PG combo could grenade a zuki tcase pretty quick, but I'm not all that up on suzuki stuff. Like we've all found with Isuzu stuff, some of these import parts can take an amazing amount of abuse before exploding.