I picked up a 73 1200 coupe last week for 100 usd .. saw it ran last year .. was the neighbors .. he or someone with less than averege brain pan over heated the motor to the point of no return....total drag..any way have been reading a bit but would like direct help in sorting out this job. I need to replace or rebuild...would it be better to replace with an A14 or stay stock and rebuild or replace with a stock size motor ... Idon't want a "Project" ... ie modifications to put in a motor that was never intended to be under the hood. thanks
david

i'd say replace. good running stock motors can be had for next to nothing.
a couple of hours and a few beers later and your running again.

i wouldnt rebuild it unless you wish to modify it

If your in the US a12's are super hard to come by. A14/15 should be easier to source.

*edit. It's a cast iron block, i doubt anything more than a head deck and a new HG should be wrong with it. Pop the head off and take it to a machine shop before you go looking for another motor.