Does anyboby know if all 425 impco mixer are the same . I running a kit on my 434 big block, 12 to 1 flat top, port and polished heads with big valves, weiand intake msd, 292 cam. I see alot of motors with 300 to 500 pony on propane. Can anyone help with some info. on what they are running.
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Help Support Hardline Crawlers :
propane
- Thread starter big ford
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TOMMY RAINS
Guest
all 425 s are the same .they make some piece that supposed to make it flow more cfm but dont know were to get it .jimmy smith builds some kick azz motors and he runs 425 s and has no issues .he has tried to run dual kits on two motors a 388 and his new one witch is a 468 and they were turds couldnt get them to run good so. if you have isusses you can ritchen it up by turning the allen head out a turn or three .
Juan_Hong_Loe
That's dumb
I know this is not what you're looking for but it's got some good info on pane.
http://www.pirate4x4.com/forum/showthread.php?t=749523
http://www.pirate4x4.com/forum/showthread.php?t=749523
s10me
Spoiled Rott'n Racing
I am not an expert on propane, but the only differences is the throttle plate that you mount the mixer on. I tried getting tech advise from Gotpropane, but they only want to tell you something if you bout a kit from them.
whiskeymakin
Well-Known Member
x2 on the got propane guy he SUCKS dicks. i was planning on buying some stuff from him but he was such a ass about it i went somewhere else. give nash lift a call they were pretty nice. 859-881-1577
altfuel1991
Well-Known Member
- Joined
- Mar 28, 2010
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I was just told about this message board by one of the guys I supplied a propane system to. He said there was discussion about Impco 425's. My company is Precision Sales & Service in Birmingham. We have been in the conversion business for 19 years and supply a lot of systems for rock crawlers.
My number is 877-403-7827 at the shop.
A 425 mixer flows between 460 and 500 cfm and flows enough fuel for 325 horsepower. On a small block it will run out of air/fuel at about 5000 rpm and on a big block around 4500 rpm. That is why high horsepower or stroker engines have to run twin mixers. The throttle bodies we use and most Holley t.b. will flow 900 cfm unless it is one of those tiny 4 barrels.
Feel free to call, email or send a message on this and I will be happy to answer your questions and you don't have to buy anything.
Email is" [email protected]"
My number is 877-403-7827 at the shop.
A 425 mixer flows between 460 and 500 cfm and flows enough fuel for 325 horsepower. On a small block it will run out of air/fuel at about 5000 rpm and on a big block around 4500 rpm. That is why high horsepower or stroker engines have to run twin mixers. The throttle bodies we use and most Holley t.b. will flow 900 cfm unless it is one of those tiny 4 barrels.
Feel free to call, email or send a message on this and I will be happy to answer your questions and you don't have to buy anything.
Email is" [email protected]"
jojo
Well-Known Member
we just run one 425 mixer on my daddy's buggy and it is a 383 stroker it puts out a few horses, several more than 325 and i know it turns a lot more than 5000 rpm's ive seen it do it 
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s10me
Spoiled Rott'n Racing
mine is on a 383 and had 426 flywheel hp with tbi, just switched to a 425 mixer and it seems to power my engine with a new larger cam and it was hitting 6500 this weekend with with out problems?
95yj
Well-Known Member
I have run 2 model E converters and 1 mixer which was recomended from heritage propane once going over 385 hp.they install these on trere company truks which are a variety of small and big blocks.they said this would deliver more fuel to the mixer.
Thanks for all the input. I talked to the guy at gotpropane and he was very helpful. He said that to get a lot more from the top end with propane you have to knock out the plate where the propane goes in the mixer. If you take the hose off the front of the mixer and look inside you will see a plate made out of steel with a round hole in it. Take a screwdriver and hit the bottom of the plate it will fold up and pull it out with a pair of pylers, I did notice a difference. I purchased three kits from gotpropane and thats maybe the reason he was helpful in some questions that I had. If you take the restictor plate out let me know if you see a difference.
altfuel1991
Well-Known Member
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When I talk about running out of air on some of these engines they might still rev up to 6500 rpm but it is like having a two barrel carburetor. You are not getting the full potential of the engine at that rpm. Most engines are not at that rpm range very often so it is not noticed. But I have had one customer call me and tell me his revved up ok in first but when he hit second it fell off badly. That's because by the time he hit second the fuel demand was greater than the single vaporizer could supply.
The restrictor plate in the fuel inlet is there for running an engine on propane. Removing it changes the air/fuel ratio to run on natural gas. You will probably find that with that restrictor out you will be using more fuel than before. Impco mixers come preset with the correct fuel mixture for the power setting @15.6 to 1 so there is normally no need to adjust the power setting. That is actually why they quit using that adjustment bolt on the front. Usually the only adjustment needed is for the idle mixture.
The restrictor plate in the fuel inlet is there for running an engine on propane. Removing it changes the air/fuel ratio to run on natural gas. You will probably find that with that restrictor out you will be using more fuel than before. Impco mixers come preset with the correct fuel mixture for the power setting @15.6 to 1 so there is normally no need to adjust the power setting. That is actually why they quit using that adjustment bolt on the front. Usually the only adjustment needed is for the idle mixture.
s10me
Spoiled Rott'n Racing
altfuel1991 said:
what does it mean if you adjust the idle screw on the mixer itself and nothing happens? I've idle my engine down to 500 rpm to see if it makes a difference and have not notice any changes. idles fine around 800 with no off idle problems
altfuel1991
Well-Known Member
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Are you talking about the idle mixture screw or the idle stop screw on the base plate?
altfuel1991
Well-Known Member
- Joined
- Mar 28, 2010
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Check the idle diaphragm behind the cover on the side where the idle mixture screw is to verify it is not ruptured. It should make a difference on idle quality when that screw is adjusted. But the idle speed is still adjusted with the idle stop screw on the base plate. Also make sure the idle mixture screw inside the cover is underneath the metal "arm" on the diaphragm and not on top of it.
Buddy
Buddy
tbs
gust want to stay to gather
I run buddy stuff on my buggy and it's about 400 hp and on Tim Cantrell his has about 550 and we never have no problem 
Glen1978
Sun does shine on a DOGS ASS!
I always thought about 350 HP was the topend for the pane, unless you got a OHG 450 mixer. BUT, there are too many throttle junkies on here running 383 strokers turning out more than that on the pane so its gotta work.
My question is........you guys running healthy 383's with one pane tank. How long does that one tank last? I know it matters how much your in the skinny pedal but on the average??
My question is........you guys running healthy 383's with one pane tank. How long does that one tank last? I know it matters how much your in the skinny pedal but on the average??
gomer pyle
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i could never get my 427w to run correctly on pane. i tried one 425 and two 425s.it would run but just seemed sick off the line and on top. i never new how much until i put efi on. i normally would go thru 1 tank a day unless there was alot of road riding (to get to the trail)and then i have used upto 2 1/2.
