The answer is simple. Change out the p85 on the 98 700 to a clutch with a 26* side angle and then ensure belt deflection is set correctly.
I essentially have the same thing 04 VES based 910 engine running an 1114 belt. Primary side angle has to match the secondary side angle in order for this to work. If your pimary is stock 98 700 then its incorrect. The old belt was just stretched enough to work. But it still didnt give you full potential of what the sled could really do.
you make it seem so simple, the primary on the bb700 does not have the same crankshaft mounting as a small block w/26*
so it would be a high dollar custom, or a regrind to make it so