Renditions of the flame thrower exhaust
Install a stainless tip that extends well past your car, install a spark ]
plug and fire it off an old 6al box or similar,  wire power to the ignition 
source with a switch within reach of the steering wheel. Mount a bottle of 
propane in the truck and run a good tested line from the bottle to an 
electric solenoid normally closed, which is switched off the same power as 
the ign. and then continue the plumbing on to a custom made fitting that 
makes the propane spray directly out the end of the pipe or old mechanical 
injector works well this injector is mounted in the exhaust tip directly 
upstream from the spark plug you installed in the tip earlier. Have fun

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Thanks for telling this guy how to kill himself!
You got to be a moron to use propane!
You can buy a kit that sparks plugs in your exhaust pipes and burns the
unburned fuel.
http://www.rodncustom.com/parts_dep/rod_n_cst/index.htm
I have installed this kit in a 40 Chevy Coupe Rat Rod and I don't worry
about blowing myself or my coupe to HELL!
You hit the switch and it momentarily cuts the power to the coil and charges
the igniter box and fires the flame-thrower coils. You pump the gas while
the switch is thrown to put raw gas down the pipes and the sparkplugs in the
exhaust pipe fires and burns the unburned gas. Sounds like a jet taking off.
It is a hit at the Sonic Cruise Night.
Watch out for the people standing behind your rod, you will BBQ their legs
if not careful.
All you supply is the coils, Sparkplug wires, Plugs and the Non-foulers that
you have to weld into the pipes.
Pretty easy installation if you read the instructions.

The Crab