baiscally....a step up from the US production 302, the mexi 302 is still a 2 bolt block but has a stronger casting with larger main bearing caps and supposedly higher nickel content. A good find, and supposedly good for another 1-200hp more than its us counterpart, but ive seen them split just as easily. The A4 302 is a 4 bolt blk and beefier by about 40lbs. The dart iron eagle is another 4 bolt blk and their more economical sportsman block is as well another beefier unit, sports 4 bolt mains and 2 bolt ends. the ford sprotsman 351 is another good option here, it is a 2 bolt block but, it can be more economical for $/strength than building a a4/R/dart 302 stoker
What are the HP capacities of each? I was looking at building/buying a 347 and had heard that a 302 block will split at or above about 450hp. I'm guessing this leaves no room for a 100 shot of nitrous or any other mod hp-increasing mod in the future.
theres no magic be all # to stock blocks... while pp believe 450-500rwhp is the beginning of a good reciepe for two 4cyls, ppl have split these with merely 300rw. Go do a search, you will likely see this everywhere. The life/abuse on the block previous to this setup is a good judge to its survivablity, and most importantly how high u plan to spin it.
assuming your block hasnt been beaten and overrev'd to piss for 15 yrs, id feel comfortable with a modest 347 with an ocasional small shot, just pick a powerband below 6200.