340 build

You're 'saving' it from a certain death, I hope.

No need for an OEM damper; the heads and pistons aren't. BTW, that crank COULD have been balanced to work with that damper and a 360 type flexplate or TC. It would end up with some pretty big holes in the 2 large end counterweights. I think I see one pretty deep hole in the rear large counter weight but dunno if it stock or not. Sounds like some prelimnary balance work is in order, to find out what the balance is set up for, before turning the crank. It is not hard to work up a bobweight with the parts you have so the shop can just test spin it with a close bobweight to see if the crank is basically in balance with no external balance parts. Stock early 340 bobweight should be in the area of 2326 grams, and the pistons and all the other parts that effect bobweight which you have should be close to stock weights. (If you have access to a gram scale, you can tell if this is so. Weigh one piston-rod-pin assembly; stock ought to be around 1635 grams (if my notes are right), maybe a bit more since the pistons are oversized. Weigh this WITHOUT rings and bearing shells.)

Have the shop look at the bores and pistons first, get some basic bore and piston diameter measurements to see where the piston-to-bore clearance is right now. And then see what the shop thinks of how the bores will hone out and what the piston-to-bore clearance will end up with hone job. Then make a judgement on being able to use the block. Do that before working the crank. The head work can go on independently as the heads can be used on any 318-340-360.

If worse comes to worst, then you can put the heads on a 360. Crank and block and rods and pistons are needed. Sell the rods and crank unless you want to run down a 340 block.

And a good calculator for CR is adequate if you don't want to do the measurements. All the part dimensions well known and you have the measurements to do it. I use the Pat Kelley calculator. (We aren't just pulling CR numbers out of thin air...)