The differance is the 86/87 Has a taller deck height, oil return line drilled in the fron of the block, and the lifter valley is casted a little different. Don't think that the hot air shirt blocks are any weaker. I have read, heard and have been told the hot air bolcks are just as good as the 86/87 blocks.
thanks for the replies. i'm trying to do a budget build motor for my 84 hurst and am exploring different options for short blocks. not looking to go faster than 12.50s.... i just want something nice to cruise and that i can rely on not to be broke all the time.
How is it stronger? Ive never seen one break on any casting in the lifter area on any engine unless the bottom end came apart. Ive seen 20 bolt pan blocks with the part # ending in 140. There are some slight variations in the oiling but thats about it. They are all equally weak especially when stock.