Pulley ID thread
Good info. Awhile back i had a 77 SB power steering. non A/C crank pulley that the power steering groove was bent flat. It was on the 360 core i bought to rebuild. I cut the PS groove off making it an alternator only pulley.
Its modified dimensions match your 70 up single groove crank pulley, so now i know this one i made/modified should work on a 70 up pulley setup without power steering.