i was reading in the faq about the alt. and how u need to dent the frame rail but then it says to use a shorter alt. belt i wanna know does anybody have that part #...?

 

I've got a b18c in my rex without any denting of the engine bay to make it fit. I don't know about a b20 but I'm using a Gatorr belt or ac delco? part# 5040300 the smallest belt I could fit and it leaves the pully with about a 1/4" of room.
I don't worry about it hitting because i have racing engine mounts that dont let the motor sway at all- nice and tight just the way I like em

 

Depending on the parts store and brand, the part number will very. I've normally used the 305K4 belts, I've also used the 310K4 belt when needed.

 

depends on the brand of mounts..some still need a dent with the shorter belt

 

I used the shortest belt i could get on there and did not have to dent the frame but it was close. Think it was a 300k4 or 305k4. i recommend at least a little dent though.