Got a 74 cutlass and the downshift switch that mounts on the gas pedal is gone. is there any reason why i couldn't use a $5 push button switch from autozone instead of buying the original part? It just completes a 12V circuit if i understand it correctly.
Thanks.

 

Any normally open switch that closes at W.O.T. works fine, so long as it has sufficient current carrying capacity. Are you planning to manually press it, or rig it up to the throttle? If the latter, you may find that you'll spend more time and money cobbling something together than just using a factory switch. FYI, the pre-1985 B/C/G body cars use this same switch for A/C compressor cutout at W.O.T. You might find one cheap at a wrecking yard.

 

AT- I was thinking you had a 72 with a 74 455 in it and we decided that by the VIN it was originally a 350 car? Or is this a different car you're working with now?

A 350 car would not have had an electrical downshift switch as Turbo 350 used a cable-operated downshift. A factory 455 car with Turbo 400 would have had it.