Hey Ty - I was able to use my stock Pistons luckly they were within tolerance - I have another set and a 66 block if you would be interested email me.
Bill
You can get all the info you need to build just keep trying. I used 1966 Dodge "D" Dart specs and have the entire Dodge information.
I had a 66 Dart 4 speed 8 3/4 put in a 4:89 gear, heavy valve springs, weber pressure plate and hot rod clutch, and some carb work. The car ran GOOD. In the 1/8 mile I was almost unbeatable in the 1/4 I would get passed by big blocks in the last 75 yards. I used M&H slicks, on the street too. Back in the day stop light to stop light in Philadelphia, PA, I dominated! Ran L stock at the track. 273 4 barrel came stock 10.5-1 with solid cam 244* duration and 475 lift. Had to sell it to continue college.
I am building another Dart auto tranny. I am thinking "D" Dart specs? Has not been driven since 1988 and I have it running. Have a gas tank problem. Once I get the new gas tank I'll be sitting on seat springs but this baby still has a lot of "snap" for an old car, and I will be driving it. I am putting a 727 trans, 8 3/4 rear end sure grip with a 4:89 gear. Have to convert to a 5 lug 4 1/2 pattern. Complete restoration in and out side! This car will fly! A Bodys forever!
Art Clark III