The Offy linkage kit comes with a new Offy manifold. It is sort of clumsy in my opinion.
Perhaps a better choice is a Lokar throttle cable kit and using a universal hot rod gas pedal made for cables or modify a junk yard unit from a mid 70's to late 80's car. I used one from an 84 Monte Carlo and with a few re-bends and simple reworking of the cable end it works excellent.
The stock GM throttle cables off those V shaped engines aren't long enough so you will have to go to the aftermarket hot rod shops for a Lokar. The 24 inch unit should be all you need.
As they say: " Minor assembly required and Batteries not included"
