We’ve sold a bunch of the adapter plates that let you mount small block Chevy serpentine brackets on the front of a big block. It’s an easy and inexpensive way to update to the latest alternator and use a single serpentine belt.
Some people don’t really care for the GM rotary air conditioning compressor, however. So here’s how you can replace it with the most popular aftermarket compressor–the Sanden 508.
For some reason, the most common multi-groove pulley, the one that Vintage Air and others sell, is a 7-groove, while the GM belt is a 6-groove. No matter, with what I’m about to share, you simply use the rear 6 grooves and leave the front one empty.
The Sanden has two sets of four mounting ears, 1 set at the front, 1 set at the rear. To start, simply place one of the front ears just behind the inner hole on the GM bracket. Temporarily stick a longer bolt in the matching rear hole. You’ll see that you’ll need a short spacer or even just a stack of washers to connect the rear holes.
Then make a short “link” to connect the outer holes of the compressor and the bracket. I used 3/8″ material. The length of this link can vary depending on how much valve cover clearance you need. I was able to keep the center of the compressor shaft in approximately the same location as the GM compressor. You’ll see that you will also need a short tube spacer to connect the link to the bracket. You could make a matching rear link but just the one seems really sturdy.
This mounting system puts the Sanden at a 45 degree angle from it’s normal position. The Sanden website says 45 degrees is acceptable and maintains the inner lubrication.
Here’s an overview. You’ll notice that in this case, the small block brackets are actually still on a small block. But you get the idea.
Here are the inner ears. The front one (to your left) is a direct mount. The rear one requires a short tube spacer.
Notice that the connecting link also needs a short tube spacer to connect the outer ear of the Sanden to the outer hole on the GM bracket.
