Is An A Body Worth It?

A few months ago I picked up a 73 340 Duster that was all original down to the air cleaner, I knew the engine wouldn 't turn over but was hoping for the best, turned out to be the worst. Got the engine out and apart and found a cylinder is cracked and both heads are shot. The block can be fixed with two sleeves (minimum) to fix the crack in one and rust pits in the other and boring but I'll need another set of heads. The block is original (it has the right numbers) and that's the only reason I even considered fixing it. The body is pretty solid but I do have some rust to fix and it needs paint and stripes which I'm going to do anyway. It has new floor and trunk pans so the car is'nt completely original now.

My question is would the car be worth it? Is the value of it great enough to fix the original block or should I, 1) find another block and heads (all other pcs are good) or 2) find another 340 engine or 3) build this 426 hemi and shove it in there.

I've wanted a 340 Duster since high school and I was planning to put this one back stock but with this development things are changing. What say ye?