any advice on underdrive pullies w/ a radix? i know a smaller crank pully will lower my boost, but what size blower pully should i use to bring it back up? also i am planning a slp zl 402 swap (forged) so i can up the boost a little.

 

I would leave my stock pullies on. I thought about it back when I had one on (radix). It just wasn't worth the extra 10hp. Also, at least 2 people that I have known of were getting KR that turned out to be the underdrive pullies causing it, as verified with the removal. You would be much better off getting a custom tune. From the power that the superchips tune leaves on the table, you won't care about the extra 10hp as much as you think, IMO.

I think the bigger problem you face is how much boost you'll get out of your 402. That thing will require much more air to make it's power and the Radix could have trouble doing it. I would be surprised if you got more than 6lbs of boost out of it. That is the reason I sold mine and got the turbo going on. Not trying to down your idea, just telling what I went through. Your results may vary and I hope it does well for you.