Propane flame thrower exhaust

[D-Day]

So, I'm taking my truck in at 9am to have a new exhaust system put on, and I'm debating the flame thrower options. I don't want one of those kits that "interrupt" the ignition to put raw gas through the engine. Hell, my truck probably runs rich enough as it is if I pull the choke out.

I might have a couple bungs put in for the spark plugs and see if it does anything; if it doesn't, I may opt for trying to rig up a propane system.

Ideas, experience, resources? Much appreciated.