Originally Posted by Julius
There is only one type of rear belt. It fits both the 710 and 720.
I do not think it is possible to put a 47t diff in a 720 but I haven't tried. I think you will have a very very tight rear belt.
I emailed Serpent USA and was told that the 47T diff could be put in the 710. But then I remembered the belt tension issue and think that I was told it would fit since the diffs from both cars share the same dimensions. Now, whether the belt will fit around the pulley is another story
And that belt looks almost like it's a different pitch, though I'd expect the belt not to fit around more of the circumference of the pulley if that was the case.