If it's not too much trouble, you can remove the transmission cover which will give easier access.
Here are some pictures to help identify the linkage.
Also check the switch mounting holes. If they are stripped, the switch will move.
Attachments
Foot Starter 01.jpg (71.89 KB, 138 downloads)
Foot Starter 02.jpg (48.6 KB, 139 downloads)
Foot Starter 03.jpg (41.04 KB, 137 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."