Several of you ask what it's advantage.. I have one on my 1972 Bronco that has the 4BT cummins in it .. I have a Np435 trans .. I love my throttle it alows me to just cruise along in the pasture checking the cows finding the correct speed to look outside more. We also loved it in New Mexico hunting from 5K feet to 7250 ft ..When you drive 8 hours a day It's sure nice to have and not have to work your ankle.
... I bought mine from a Jeep 4x4 Magazine and I think it only cost about $30.00. Mine has a button on the side you can twist for lighter or harder pressure on the lever.
Old cars and trucks used to come from the factory with hand throttles. I have a 1949 chevy truck that has a hand throttle. Is just like a choke cable. Used to keep the rpms up to warm up, idle up, or to operate a power take off unit off the transmission, such as to operate a hydraulic pump to lift a dump bed.
I used to put the truck in granny low gear and throttle up to walking speed and walk along side the truck/trailer when hauling hay. Saves labor! No need to have one person to drive the truck. Although previous to being able to tote and toss bales, I was the driver. Btw, when you are 8 and can't reach the pedals, a hand throttle works great to give it gas.
Right, lots of uses in the old days and they put 'em on trucks as late as 1974. We have a '74 Bronco with a factory hand throttle, and it's great. That's really funny about the 8 year old. When my son was 10 he could barely reach the gas pedal on my CJ, and it had a bit of a sticky throttle at tip in. So we'd be in a big mud puddle and he'd push it...nothing...push harder...nothing...push harder yet...POW! 325 hp making four giant rooster tails with a 10 year old behind the wheel looks pretty cool.
If I had all the money I spent on cars, I'd spend it all on cars.