Big Bore Question? Trying to figure out what I have??

[MM800]

I have a set of cylinders, pistons and a head. I cant remember what they are? The cylinders measure 74.5X. Right in there some place. There is also a thick base gasket spacer. For the life of me I cant remember what this was??? Ive had it about 16 years. Any Ideas? What of the skirts is broken.