Technical SBC 350 Pulley setup for alternator only

That adjusts the alternator belt , not the forward belt ( closest to the radiator) doesn't it ?

 

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I don’t understand your “?????”.. dirt stockers and super stock style engines at all the tracks we run at use the “extra” belt from the water pump to the crank which what I was referring to and so was the poster. It’s a dedicated belt. They have an alternator and PS pump belt also.

 

in post#32 above are the standard 68-9 corvette belt routing combinations , I don't see a single crank to water pump belt , if , as you say , racers used it , it was a short term ,non adjustable race thing that would have been impossible to properly adjust belt tension .

 

Being the belt in question is 1/2 way wrapped around both crank and waterpump pulley, it doesn't require banjo string tight to do the job without slipping. Just the force it takes to lever the water pump pulley into place stretches the belt out enough to do the job.

 

As stated earlier, I ran an aftermarket alt bracket for short pump. The single belt ran the crank, water pump, alt nothing else. The alternator was mounted high, above the drive-side valve cover. I did not have room to hang the alt off the side of the engine on the drive-side. I ran one belt and, due to the location of the alternator due to the aftermarket bracket, there was almost no contact between the single belt and the water pump. Stupid design. I then bought two new double-row pulleys, one for the water pump and one for the crank. I then installed a second belt, this one wrapped around the water pump and the crank. There was absolutely no adjustment available ... buy the "correct" belt and run it. Now, due to the fact that the small/short belt covered almost three quarters of both pulleys, there was no apparent slipping even if the belt tension wasn't what we know to be perfect in a normal, adjustable situation. There is nothing short term about this mod, it just plain works. That being said, I have no idea if it came factory on anything.

Before I added the second belt, I had problems with the lone belt (when used with the poorly designed bracket I bought) being thrown. I then ran it with the two belts (the long one and the crank/water pump one) for a while then decided I wanted to add power steering so I removed the short pump, alt bracket, and water pump pulleys and went to a standard long pump with factory bracket and pulleys.

I initially bought a short pump, new single groove water pump and crank pulleys, and an aftermarket drive-side bracket assembly. I then removed the single groove pulleys then purchased and installed double-row pulleys and ran the extra, short belt. In the end I removed all that crap and went with what I should have gone with in the first place ... long pump, factory brackets and factory pulleys. With the long pump and factory pulleys (which located the alternator in the correct General Motors approved location), there was no need for a second belt that wrapped around the crank and water pump.

Bottom line, the single belt from crank to water pump does work, it's not just for race cars.

 

Here's the way mine looks.

 

This is what I gots, About as simple as can be... using the dreaded electric fan.

 

You will also need to change the distributer.
Decide if you are going to run a long water pump or a short one. Next you need to source pulleys for an SBC running the pump that you decide on. You can do that several ways, you can go to a wrecking yard, or you can ask your buddy or you can call your favorite catalog speed shop. The last is easiest and unless you just have time and live close to a U pull it probably your best bet.

Note: do not buy a used or rebuilt water pump. Save yourself a headache and buy a new one.

 

The first two diagrams show a belt (labelled 2) that goes around just the water pump and crank pulley.

All of which isn’t really helping the OP

I like to run two belts round the water pump as it gives you a fail safe, I always think the SBC alternator belt is really long and prone to coming off.

 

I stand humiliated & corrected , even if its a half -assed configuration !