340 8 bolt crank info wanted
If the pan was off you might find the last 3 digits stamped on the front the front counterweight. See picture in this add for a 3.51 stroke MP crank with the stamping 710.
[FOR SALE] - Mopar Performance crankshaft
By the way Mopar Performance made. 3.71” stroke 8 bolt flange forged crank who’s last 3 digits that should be stamped on the front counter weight should be 714. This strike would be close to your number calculated.