high rpms problems jettin???

[The_dew_man]

I just got a new pipe for my 350x and it snaps and pops at high r's. Tried differant jet sizes. stock jetting on a 86 350x was 138 and 45 (if i remember right). Right now i have 140 and a 50 in. The plug looks a little white. Goin work on it tomarrow just thought i would ask for some help so i can go ride that night.

Thanks