The other issue is the gas pedal. I don't have a GMC one but the picture is from the 55-59 Chevy FAM.
Obviously this design works with a bell cam/crank mounted on the engine which the 292 does not have.
Many choose to buy a new pedal with a pivot (bell crank) that is made to mount on the firewall.
You decide what you want.
Attachments
Throttle Pedal.jpg (107.08 KB, 101 downloads)


"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."