musman

I just purchase an original shaker assembly for my 351W for my '69 Mach1, i'm pretty sure that the flapper motor is in need of change...as anyone ever replaced one with an aftermarket unit, i think that the original one is welded into place....also i would like to know how it operates exactly.....i know it has something to do when the four barrels kick in.....but does the carburator pushes air or it draws air?
Thanks guys