C-3, alternator pulley 454

[D S.]

My 1970 454 alternator currently has a two belt pulley. Is this correct? I have power steering and AC. I kept seeing those "correct" single belt pulleys on eBay that are one inch thick on one side and look like they are made of aluminum stock. Then in a box of parts I discovered I have one, too.

Thanks,
Scott

[Jack H.]

Re: C-3, alternator pulley 454

Single groove pulley for '70 BB w A/C & PS is 3 inches in diameter and THICK cast aluminum. Very similar to the same pulley used on base BB except for the offset on the back side (thickness from pulley groove to rear of pulley). The reproduction pulleys for this application are generally milled from aluminum stock and detectable as not being cast like factory originals. Your copy of the AIM will show you belt routing (what belts go on what tracks of which pulleys) for the various bolt-on engine configurations (with PS, with A/C, with PS & A/C)....

[Joe L.]

Re: C-3, alternator pulley 454

Scott-----

I don't know of a Corvette application that originally used a multi-groove alternator pulley. Some other Chevrolet applications did, though. However, I won't rule out the possibility that some Corvettes originally received a "substitute" pulley with 2 grooves, possibly due to a shortage of the single groove pulley scheduled for installation.

[Joe L.]

Re: C-3, alternator pulley 454

Jack------

I am not aware of any Corvette alternator pullies, original, replacement, or reproduction that are manufactured from aluminum. All that I am aware of are either manufactured from fabricated steel or machined steel. Most of the big block pullies were machined steel. It is true that the manufacturing methods for original pullies and later SERVICE or reproduction pullies may be different. There were usually no machine marks on the originals and later SERVICE and reproduction often evidence these marks. However, I don't think that the originals were a cast part.

The original pullies were usually clear zinc plated which might make them APPEAR like aluminum, but I don't think that any were.

[Jack H.]

Yeah, I think you're TOTALLY right here, Joe *NM*