Where could I find the specs for a GM crankshaft casting number 6223

All BBC # 7114 cranks were crossdrilled & tufftrided from the factory & only installed in original L/88 & ZL/1 427 engines.All GM BBC #6223 cranks that were factory crossdrilled are tufftrided, whether 396 or 427, they came in SPEC HI PERF solid lifter engines only from the factory. I believe the 6223 crank was primarily used for 396 applications and has a 3/4" thick front counterweight. If the crank is a dull gray color and the mains have been cross drilled (a hole from one side of the main to the other), it would have been used in high performance solid lifter applications. Cranks used in 427 engines use a thicker (7/8") front counterweight to balance the heavier pistons and are forging #71XX. On a non cross drilled crank, the #1 and #5 mains will have only one hole, cross drilled versions will have two.

This is all the info I could find at the moment, but I will ask a friend of mine who is a mechanic at the Chevy dealer here and maybe I can help out further. If I find any more info on this, I will post back immediately following. I hope this will help in the meantime.