Holy crap!

crackedback said

3.4 stroke according to the builder

and 13 blocks as backups when the stock block craps the main saddles

going in a 68 Dart

Click to expand...

If that's the case, they offset ground a stock 383 crank, probably. Either that OR the builder just rounded off the 3.375 to 3.4. The latter is probably the case, I bet.