Remember with Pole Position you have a single button shifter in there, the game defaults to low gear unless that switch is being held down. Problem is that Pole Position in MAME doesn't work like that, instead it uses a button that toggles between high and low gear, so the real shifter won't run the game properly in MAME (or at least it didn't back when I built my conversion). I ended up contacting a guy on BYOAC that built a conversion as well. He recompiled MAME to support proper shifting behavior for Pole Position and Pole Position II, which is what I ended up using. The downside was the recompile was for DOS MAME v0.56 - quite ancient.
I don't know if MAME has changed how PP and PPII work these days. Alternatively I was thinking of installing an Atari 4 gear shift (reverse N) since that would alleviate the problem and also allow me to play more games. As long as you boot the game in 1st or 3rd gear the high / low shifting in Pole Position / Pole Position II would be fine, since the toggle would always come on an up/down shift (with the proper key setup)...
LOW LOW
|....../|
|..../..|
|../....|
|/ .....|
HIGH HIGH
I ended up not doing the above since I decided to move onto another project after moving and didn't have the space.
The entire internals of the cabinet were completely trashed (shot wiring, tube neck cracked, boards shot, speakers rotted, ARII boards oxidized to hell, etc.) except for the cabinet itself and the control parts. I went super cheap with my conversion, I actually ran all my control surfaces off a hacked mouse. I used the mouse encoder for steering, one mouse button for the pedal (reversible conversion with a switch), the other mouse button for the shifter. The coin mechs ran to an internal keyboard that I did a single key hack for coin up on.
Even with the limited setup (looked stock from the outside) and old version of MAME, I had the following games on it...
Badlands
Championship Sprint (Revision 3)
Danny Sullivan's Indy Heat
Fire Truck
Konami GT
Pole Position
Pole Position (Atari Version 1)
Pole Position (Atari Version 2)
Pole Position II
Pole Position II (Atari Version)
Pole Position II (Bootleg Version 1)
Pole Position II (Bootleg Version 2)
Stocker
Ironman Ivan Stewart's Super Off-Road
Ironman Ivan Stewart's Super Off-Road Track Pak
Super Sprint (Revision 4)
It worked pretty well, I'll have to say. And ran for a couple years without any problems until I took it all apart.
(I did put a bigger monitor in there eventually.) I built the monitor shroud by hand since the original was garbage.