So i plan on buying a rebuild kit (Master Engine kit) from mustangs unlimited and was just wondering what the difference is between the kit for early 1972 and late 1972 and if it really matters. (and what date seperates the early from the late?) Any help would be apreciated.... My car is a sprint made in april. (im pretty sure, ill check tommorrow.) The only mods done are intke, carb and long tubes but its a tired old engine and needs a proper rebuild.

 

i imagine its the compression ratio of the pistons dropped in 72

 

I am not sure but I know that somewhere in the latter 70's or early 80's they changed from a 28oz embalance to a 50oz embalance for the crank, other then that there could be a slight difference to the timing cover as where things are located, such as thetiming indicator, flow of the water pump (but I think that's around 82ish), etc. I don't know of any internal changes other then maybe the piston design. Hopefully one of the pros will chime in here soon.