302 blocks

a 331 with a 150/200 shot will split the stock block. forget about the 185's go 205's.

u have 4 choices - mexican block or aftermarket race block, SVO R, dart or A4.

not true to the bset of my knowledge, the older pre-1980 blocks where made using the old non-thinwall casting design called a middle weight but this had nothing due to the strength of the block itself (This blocks also had other provisions on it for lincoln). the 1980 and later blocks ( not the mexican) use the thinwall casting, the blocks where upgraded again in 85 for roller lifter and again in '86 with thicker decks, cylinder walls etc. The mexican "middlewight" blocks are casted like the older 79's but they don't offer anymore strength to the block itself. If you blow the block invest in a dart or world, once you get to that 500-520crank hp range it's time to start thinking that way.