I know packet radio has been used by other HAM radio operators for a long while, but it never really got super-popular, or very fast. Iīm also unfamiliar with the FCC regs in this matter, I know they tend to have panties bunched when there isnīt voice communication involved for private/business use. So long as that doesnīt concern you much your probably on the right track. Just with some rather unknown caveats.
It is likely however itīd be less costly and less of a headache to just slap good antennaīs down with 1-2watt amps on them. If your in the pit, you can probably put up a good one thatīll get line of site, no? Something like this with an amp comes to mind for the pit, on a good length pole with ties. Then of course a decent one on the car itself. Any method you decide on will require a good antenna with good placement, so my first inclination would be to go this route unless thereīs something major that would truly hinder it.