Started tear down last night. It is in fact the original engine. Decided to tear it down since tranny died. Hate to tear down a running engine,but the seals and gaskets are all shot so gonna re ring it, clean it up. Get valve seats done and put a hotter cam in it. Also rePlAce timing set,water pump,fuel pump,oil pump etc. 350 two barrel,number 6 heads, turbo 350 tranny,12 Bolt rear which I am still seaching for a code on. ..

 

Cool car. Looks like it needed refreshing, you'll be happier with it in the long run. Keep us posted.
Scot

 

My guess would be a 2.56. That's what was in my 70 S.