You also need to tell us what truck you are working on. If it is an AD/ND the one Performance Online sells will work with a manual transmission. The one CPP sells has a larger booster. It may be the one people have had trouble fitting. If your truck is older than an AD, I don't know about them.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.