I need to know what size belt for smog pump removal.....

[mustang1313]

Hi guy's I just put my gt 40 heads on with 1.7 rolloer rockers, I removed my smog and I have no A/C, and I'm not sure what size belt to use I tried 790k6 but it was to big can someone help me out here. I think I night need a 711k6, but I'm not sure

:SNSign:

 

[Kabuki_notch]

I just put a 72inch on my car I removed the smog pump and deleted the a/c for the time being.