I am not going to doubt you but I would like to ask how.. I know the 12:1 compression has a lot to do with it because with that compression you are not relying on flow. I had the system for a year and my low end was awesome.. very very sensitive.. it would jump just blowing on the gas pedal. I tried EVERYTHING.. I even installed an o2 sensor and a air fuel mixture gauge to make sure it was tuned perfectly. Since my dizzy was an msd I went through multiple spring combinations to find the best one. On the dyno ( I still have the dyno sheets hanging up in my garage ) it showed that at higher rpm ( over 4200 ) the engine was screaming for air. It just could not get enough air. The same exact engine.. nothing changed except timing and the carb and I had a 100Hp increase. Real numbers on the dyno. I own a web development company and one of my clients is one of the single biggest propane guys in the country. I live in MN and the guy that gotpropane buys his stuff from ( Carburation and Turbo ) is located an hour away. I talked extensively with both of them and even took my engine to the carburation and turbo guys to tune for me. The end result from their mouth was it's not possible to get that horsepower out of a single 425 carb. Higher RPM needs more air it's just physics. A 425 carb only flows in real number about 416 cfm.
Propane has more octane.. that is why you can run more compression BUT propane has lower BTUs which means less energy. Loss of hp...
Also, watch out for the Gemini brand evaporators. My got propane kit came with them instead of the real impco brand. Gemini is made is china and mine was pitted all around the fitting area so it leaked. I ended up buying a impco one from carburation and turbo.
I am not trying to argue or disprove anyone. I am however trying to real real information on here so people don't make the mistakes I did. I believed all the postings on all the boards about how propane is the second coming of jesus, how your vehicle can run upside down ( it can but you have no oil pressure ), how it starts right up ( it does BUT it will also flood if you don't have a VERY strong spark ), poor man's fuel injection ( true it's cheaper but not by much. When all was said and done I would have been better off just putting in the FAST system )
Before you go propane do yourself a favor and just research. I know someone with a big block FORD that claims over 500 HP with a single carb. He was part of the reason I went propane. Truth is that engine was never dyno'd so he don't know. Engine is strong but like mine it was a dog at higher RPM..
try
http://www.propanecarbs.com for information. I do not work for him, he was a client and I built his website but that is where it ends. I get no kick backs etc.. he will tell you the truth. Also check out
http://www.alternatefuelsracing.com which is a site my company did NOT build but it will give you more real information about hp and propane. This car below is one of his cars.. As you can see.. not just one 425 carb on it.
To all those that use propane and love it, I mean you no disrespect. It's not for everyone. Wasn't for me or my engine. Different strokes for different folks
