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5.7 Vortec To Tbi (propane Conversion)

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Hi this is my 2nd post on the forum. I'm thinking of taking the sequential fuel injection off a 97 5.7 vortec and putting on an intake with throttle body injection ; like the 95 TBI . I know this sounds backwards but if I do this I can install an impco dual fuel (propane/gas) conversion. This conversion would be the old Fumigation type propane system (cheap to convert). The vortec sequential injection will only allow and expensive propane injection system $5500. If I was to put a fumigation system on (old impco system) the 5.7 vortec intake holds too much propane vapor and tends to backfire damaging the top end and melting the plastic air intake,not good!.GM performace makes an intake for vortec heads that a TBI can be installed on; Part # 12496821.I think guys with TBI 350's use this intake to install vortec heads on the older style 350. I haven't seen any posts putting a TBI on the 1996-1999 5.7 vortec.I know that I could put a 95 ecm and wiring harness on to make the TBI work but ignition and emission controls would most likely not work with the 5.7 vortec. The other idea would be the existing ecm with some sort of patch for a TBI ? I know the fuel pump would need changing ( to what ?). If you could get the TBI on and emissions not too far off the original sequential fuel injection system you would have a very efficient 3/4 ton truck.Any ideas on wiring emissions etc.to make this work ?

Thanks ahead of time hope to get some hotrodden advice.

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Hey Oakman,


I am almost in the same boat as you meaning I want to convert a chevy to propane. I have looked at these sites and will be calling them on Monday to see if i can get a system.



















If these are the companies who want $5000 bucks for a conversion I apologize up front but I do not know who you have talked to yet. Ecofuel seems to have many GM lpg conversions.


My question to you is where would you buy the fumigation equipment, ebay or directly through the manufacturer?


I just got rid of my factory converted Ford F-250 dedicated cng and boy did I learn a few painful lessons.




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