That is where I got mine....

 

I think they come with 3.5". That is what mine came with on the snout. If you don't have one of the tools you may need one to remove the pulley. I would think switching from a 3.5 to a 2.7 would require a new belt. What size lower pulley do you have. If you have a stock lower pulley and and 2.7 upper that is a lot of boost unless you have a built engine. I get 22 psi with a 2lb lower and 2.5" upper.

 

Thanks, Easterbunny. Wow, that is a lot of boost for a 2 lb. pulley. I have a 6 lb. lower, and according to KB that should yield about 18 lb. of boost with the stock upper pulley. I do have a built bottom end, and am looking for about 22 lbs. with the JDM ported heads. Maybe a 3" pulley would do the trick, what do you think? Plus I think I'd be less likely to encounter belt slippage with the 3", huh?

 

People get different amounts of boost from the same pulley size.
I get 26psi with a 6lb lower(8.9") and 2.5" upper and 15psi with 6lb lower and 3.5" upper.
I just ordered a 3" upper from Tom this morning. I am hoping to get 20psi with it and the 6lb lower.

 

Sounds like you need a 3.0" or the 2.9". As far as the belt, I would use the Gaterback 4080685 belt. We have both in stock, they will be on the site tomorrow.

 

I think I'm using a 68" belt the 3.5" upper and 8.9"(6lb)lower. I do have the stop knocked off of the tensioner.

 

You guys rock! Thanks.

 

You KB guys have me to thank, I sent Jim my 3" KB pulley so he could get the bore size right.

Yes the KB pulleys are now available.

 

Thanks.