The kit that i have on my car was bought locally here in vancouver...the guy's name is bad pat...i do not know if he still sells them...but he is always at car shows locally here selling t-shirts..he drive a 30/31 model A pick-up...the kit included a circut box, instructions and 2 spark plug bungs (to weld in each of the tail pipes) you have to supply (depending on how many exaust tips you have) a coil, sparkplug for each and a 2 position switch.
you rev the engine (when ehaust tips are warm) hit the switch and, while the engine is slowing down pump the gas...the raw gas goes thru the ehaust pipes and is engnited by the spark plugs.
tip: install the plug 2\" away from the end....AND if possible make the exaust tip's a large dia....it not the flame is small and very loud (shot gun)
hope this helps