propane questions.....

[rob h]

i am looking into running propane in my small block, its a 350 .040 over with domes and 12:1 comp.....its around 400-450 hp.......alot of people say that the impco 425 kit will work good but not over 5500 rpm(got propane etc), ive found decent prices on the 425 kit but the situation is 50-50 that it will work good, i was told to run 2 425s and others say one will do me fine, anyone have it on a moderately worked 350-400...? looking for some help....thanks..any input will help..

 

[dfl701]

Are you buyin a kit or putting one together yourself?

 

[80' 427]

It will restrict hp up top with a single. I know some guys run 2 but it doesn't work that well because they are hard to make work together. There are some 1000 cfm carbs but they are expensive. It will loose some horsepower but I guess you have to decide what you want/need. If it was me I would try it with a single and see. You can always buy a second. It will work above 5500 it will just become a restriction. I have a friend that turns his 13 to 1 427 5500+ with propane looses some horsepower but he can afford to buy fuel for it.

 

[rob h]

im going to buy a kit, i found a whole kit that comes with all the parts except the tank brackets...its 655. shipped...and propane is less than 2.00 a gallon......thats part of my reason to switch to propane so i can afford to use my truck my truck. im not sure what to do but if it works and runs fine but a lil restricted i can handle that, just as long as my motor doesnt run like a stocker....

 

[AussieK5]

I'd not run propane on a true 12:1 motor, they like a bit more static compression, but 12:1 is pushing the friendship in a huge way. Sure propane has a slow burning rate and higher octane rating, but this is only at slow engine speeds, as engine speed increases so does engine turbulence which lowers the useful octane rating of propane. In what rpm range does your 12:1 SBC make its 450hp, its not going to be sub 3000rpm that's for sure.

Whats your intended use?

Good guidelines to keep a propane engine happy are;
10.5:1 for light duty passenger car applications.
10:1 for pick ups or similiar that see light towing duties.
9.1:1 to 9.5 for heavy towing or high rpm use.
(Ref: Propane Fuel Conversion - Jay Storer)

Propane in the right application is a great fuel, but I think your buying into a world of trouble installing it on a 12:1 450hp SBC.

Grab a good propane book from ebay/amazon and save yourself a lot of hassle.

 

[NEK5]

im going to buy a kit, i found a whole kit that comes with all the parts except the tank brackets...its 655. shipped...and propane is less than 2.00 a gallon......thats part of my reason to switch to propane so i can afford to use my truck my truck. im not sure what to do but if it works and runs fine but a lil restricted i can handle that, just as long as my motor doesnt run like a stocker....

Care to share where you found said kit?

 

[rob h]

nash forklift, they have a store for auto only on ebay...type in propane conversion and skim thru to find like a kit for the 22re and at the bottom they have a ebay store and i called..the guy is bill nash and hes real nice to talk to...he has the kit for 655 without the air cleaner and tank bracket ....the propane carb mounts to your baseplate, im not sure what to do at all, this guy and got propane say it will work good for me but im not sure yet i wana do alot of research and get suggestions b4 i buy....but my motor is far from stock thats y i have to really check into it....

 

[rob h]

My motor makes the high power around 3500-5500 and pulls good but it never or hardly do i crank it up to that. i usually go to 4500 and thats it..the motor really is enuf for me at the 4000 rpm level..thats y i said propane and this kit.......anyone any ideas will the 425 do ok..?...im looking to drive it more often..ill have to look into the propane book that was spoken of also..