PULLEYS & BELTS

I'm sending this out after trying to do it inside another subject and realized that since there's no "most current updates" posted against a given subject, there's no way anyone would ever be able to find my comments in the new web site design, soooooo....
I'll start a new one hoping someone can help me.
I have four belts I'm trying to put back on a refurbishing project in the engine compartment of my 1971 SII FHC (6 cyl). The biggest belt should fit on the pulleys closest to the block that work the water pump. But even after relieving the tension of the spring-loaded middle pulley, I can't get the belt to clear the out edge of the upper and lower pulleys (too tight by a fair amount).
The other three belts will drive the alternator, the power steering, and the AC, which will be adjustable since these units bolt to various spots around that area and don't have to require the belts to "slip over" the pully edges.
If it's determined that I'm just not prying hard enough to clear the edges, does anyone have a description of exactly how to do this. The picture frame is pretty much in the way of doing anything with a screw driver.

Thanks.