Something different Building for MPG.

How about a late 318 roller motor with super light rod/pistons, maybe 9.5:1 cr. The pistons should be coated and you could use clevite h series coated rod and main bearings. The cam would get durabond coated bearings, it would be a low rpm high vacuum type with low valve spring pressure and aluminum rockers. Top it off with a set of 273 heads and the old offy dual plane intake. Use the 833 O/D trans and a 3:23 rear... Stuff that puppy in a 2800 lb car...what do you figure it would do??