One of the early challenges that I identified on my Cummins installation was the throttle linkage. On the stock truck, the gas pedal pushes on a rod that works a bellcrank on the end of a rod that runs across the top of the bellhousing to another belcrank to a rod... until you get to the carburetor. On the bread van that I got the Cummins out of, the pedal pulled on a cable that ran through the firewall to a cam on the fuel injection pump on the left front of the engine.
I spent some time looking at various solutions involving either using the stock gas peddle with a reworked linkage in order to connect to a cable, or at using the Chevy pedal in the truck. Both solutions seemed to be too much of a Rube Goldberg setup for me to feel comfortable with implementing either one.
As I got closer to completing the engine installation in the truck, I became a little more concerned about my lack of progress in solving the throttle situation. One day, while a buddy was looking at the truck, he suggested that I peruse his street rod magazine collection. One magazine's featured product was a replacement gas pedal called the Lokar Eliminator. It is designed to fit through a hole in the floor (or firewall) with a cam on the engine side of the panel for the attachment of a throttle cable. It looked promising, so I looked it up on their web page and ordered a unit and cable from SECO Performance in Birmingham, AL (a street rod shop).
Once the Lokar pedal arrived, I removed the original gas pedal from the M37 (had to grind off the screw heads they had rusted so much) and put it in the box of spare parts. I then placed the new pedal on the floor to check alignment and marked locations for the mounting holes. I then placed the pedal arm through the hole in the floor and bolted the cable attachment plate in place. The design of the assembly is that the floorpan then becomes sandwiched between the peddle base plate and the cable attachment plate.
I then attached the 36" Hi-Tech Throttle Cable to the peddle bottom (leaving the "c" clip off the connector pin in case I wanted to change from one mounting hole on the pedal rod to the other) and routed the cable up the firewall and along the left side of the Cummins. I trimmed the excess length off the cable and attached it to the cam on the fuel injector pump. I then tightened the mounting nuts on the cable that sandwich the bracket on the driver's side of the pump housing to anchor the cable in place. I used a pair of 5/16" fender washers in addition to the cable nuts since the bracket on the injector pump had a large rectangular hole setup for the plastic lug on a Chevy throttle cable and I wanted to insure that the new cable wouldn't move.
Final steps of the installation was to install the "c" clip to lock the cable mount pin in place once I verified that I was getting full throttle at the injector pump when I had full pedal travel and to block off the original pedal hole in the firewall.
Lokar caters to the street rod crowd and has a webpage at: http://www.lokar.com/
I purchased the parts from SECO in Birmingham at 1-800-633-3864 or 205-251-3254. They have a web page located at: http://www.secoperformance.com/
Lokar FMG-6098 Billet Aluminum Eliminator floor mounted gas pedal with insert (two rubber strips)
TC-1000HT36 Hi-Tech Throttle Cable
Pair of 5/16" fender washers