Here's how I did a mechanical linkage on my 37 PU.I first tried a Lokar cable of the original throttle pedal bellcrank on the side of the block. It worked but the cable had too much fricton,required a pretty stiff return spring. Removed the stock linkage,put in a typical hot rod pedal,made up the rest from a discarded GM linkage.Hardest part on an inline engine is making up brackets,I mounted the bellcrank on the intake. It all works smoothly with a light return spring.
home made linkage