Is an 8 rib pulley upgrade really necessary?

How many of you guys are running 400+ bhp with 6 rib setups?

I realize I l live in a high DA area which makes a big difference but...

I'm already running a 3.125" on my centri (3.33" is what Vortech normally equates to 10 lbs). My tuner says I need to upgrade to an 8 rib setup if I want more than 8.5 lbs boost. If I go any smaller I'll lose too much surface area and just slip. I trust his judgement, I just want to hear opinions.

Thanks for the feed back, guys!

Just to reiterate, this thread isn't about challenging my tuner's credibility. He's nationally known, published on the topic, even been on TV and no, he's not selling anything. Moving on...

darkside03gt: Thanks for the link. I'll follow up.

trinity-gt: No, I don't smell any burning or hear anything. Haven't tossed a belt, (but I'm on the smallest belt I can go). Pull #'s have been consistent, but I think this qualifies as abnormally low.

I know that if I was at a lower DA, I would be running considerably higher boost (The Vortech techs have confirmed that as well). I started to experience belt slip at 325 bhp with a 3.6" pulley, but that was in NY where racing conditions are ideal. Out here, when I added the Power Cooler, the pulley was reduced to 3.33", which as mentioned before, Vortech equates to 10 lbs under normal conditions and pretty much max for what the SOHC was intended to go. A 3.33" pulley got me about 7 lbs here. I dropped to a 3.125" and brought it up to 8.5" lbs.

What I'm trying to determine is, would it be throwing good money after bad to buy yet another smaller pulley (2.9"?) and then another belt (and there's still no guarantee I'm at 10 lbs) or would it make more sense to just upgrade to the 8 rib at this point which is considerably more expensive.