6 cylinder in mine and there's plenty of room for an extra pair of cylinders, electric fan Infront of the radiator.

I have a th700r4 trans which is nice and easy if going with the 350.
Judging from my engine swap, You will need a new trans cross member, mount for the hand brake piviot, fuel pump, and suitable engine mounts. You might need to cut out about 6 inches from the sump to clear the engine crossmember, you will have very little clearance between the steering box and the exhaust, block hugging ones should be ok, but check. I saw a mighty Max front section used in a hotrod the other day and they had used a rack and pinion from something along with Montero? Hubs with the steering knuckle at the front for extra clearance.
I would recommend converting to power steering