well i am lucky i guess, I only paid $300 for the enginge, the fellow I bought it from didnt know what it was. I did the research on the numbers and came up with the zz4 factor. my concern now is that it may have been a zz4 that has been rebuilt , i found a reman tag on the side of the engine (glued on) that says remanufactured with a number on it..if this is the case I dont know what cam is in it . but it does not have aluminum heads cast iron heads that look to be late 80s 305..will take it apart..would like to know the condition even if it does look good. thanks