I am currently assembling the Y-Block for my son's 1954 Crestline and I want to add A/C to the car. I have purchased the required brackets from Vintage air, but I didn't want to buy their accessory pulley. I want to keep the engine looking as original as possible, so a machined aluminum pulley wasn't going to cut it. My question is; Do I need a two groove pulley or will a single groove work? Silly question, but I want to get it right the first time. Thanks!