No such animal. All 455's used the same upper arm with or without ac. The hole at the end is just not used in non AC applications. Car Craft built a Buick engine several years ago from a 72 Electra and the idiots cut the end of the arm off. The arm is the same for 71-74 455's. Not sure if 75-76 is the same. 70 was different.
I have one, but it is up in my attic of the garge. I will dig it out this weekend (Sunday) and send you a picture. send me an e-mail to: sunbuick@aol.com