Hello all. I picked up a mp122 from a member here on this forum and had a few questions before the install. Im wondering how much hp I would gain out of 8psi and 10psi boost roughly with the setup in my sig. (5.3L) What size pulley would i need roughly to achieve these boost numbers. It has a 3.2" on it now but have no idea what it will make. I know this is hard since every truck's setup could make different numbers. Im just looking for a starting baseline. Thank you.

 

IIRC when I had my 122 on my 5.3, a 3.4 pulley nabbed me around 5psi or so. So, for every .1 you pulley down, expect 1psi boost gain. Now, this was an internally stock 5.3 with stock 706 heads (i believe they were 706).

 

3.0 5.3L MP112 @11psi

 

Thanks for the info guys. This should give me a bit of an idea for a start point. Anyone else? Post up please.

 

5.3L MP112 3.3" 8psi