I've got a couple gatorbacks I just remembered having in the basement. I wasn't planning on using another since the one I had on my SSEi stretched a good 3-4", but if I have an extra I might as well put it on so I don't have to spend money I don't have now.
Thanks in advance.

The #'* I have are 4060715 and 5060715. Will either of them work? I'm not really seeing the difference in them.

Here'* a list of the belts and info that might help http://www.goodyearep.com/productsdetail.aspx?id=3128

i have a 4060715 on my 3.4 and it barely fits

Those are both 6 rib 715mm belts. Getting that on a 3.4 is tight, the 3.6 your going to need a 725mm