Well, here's a universal V8 system from NOS, but this is something almost anyone can build on their own for far less money.
Holley Performance Products Sniper Universal Wet Kit*07006NOS
Basically, you need a bottle, hose, nozzle, toggle switch, vacuum or oil pressure switch (so system can only be activated when the engine's running), and 2 lockoffs (1 opened & closed by the vac or O.P. switch, the other opened by the toggle switch.) Get the bottle from Amerigas, Merriam-Graves, or any welding/industrial gas supplier. Hoses and necessary fittings come from any hydraulic shop. You can get a nozzle from a speed shop, the vacuum/oil pressure switch and the lockoffs are available from any forklift dealer, and if there's a Skyjack aerial lift dealer nearby (United Rentals, for example), you can order the following part numbers: (part numbers may have changed, my CD manual is over 4 years old.)
2ea 125793, LPG shutoff (lockoff)
1ea 111623, switch, vacuum safety
These are both threaded for 1/8" NPT.
There's also an adjustable nozzle that I couldn't find the Skyjack part number for (it's been a long time since I worked on one and forgot what it looks like LOL), but this
Valve, Flow Control - Pneumatic Flow Control And Needle Valves - Valves - Pneumatics & Hydraulics : Grainger Industrial Supply
or this
Valve, Needle, 1/8 NPT - Pneumatic Flow Control And Needle Valves - Valves - Pneumatics & Hydraulics : Grainger Industrial Supply
should work just fine. Start with it backed off maybe 1 turn from fully closed, and adjust for desired power. Mount away from the engine, the brass one is rated for 140F max and the plastic is 200F.
