[dirtyjim]

i have a late astro van 8" booster bolted to the firewall on mine, if i had to do it again i would buy the bracket from captfab. it might not be flush with the bracket but it would be a lot easier.
the studs will have to be removed and possibly the hole in the firewall enlarged depending on the booster you choose. i took the studs and reversed them to help hold the brake pedal in position while mounting the booster. its not necessary to do this but my brake pedal assy kept trying to twist to the right when i was mounting the booster. i did have to make 4 spacers so the booster would clear the heads of the studs, if i remember correct 3 of them were 1/8" long and one was 7/8" long because the sheetmetal behind it was double layer and stepped out 3/4" under the dash.

to connect the booster to the pedal i turned some 7/16" round stock that i threaded 7/16-20 on one end and counterbored to fit the booster shaft on the other end. then welded it to the booster. i could have just threaded the shaft on the booster and tapped the end of the pedal shaft to fit.