Thread: Holley-proform Carb Issue.

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Originally Posted by gassersrule_196

ever since i put that POS proform on my car i have had nothing but trouble. and i mean years of trouble. i am saving up for a demon as we speak

I don't know if you want a Demon. I have seen a lot of complaints about their QC including metal trash in the carbs out of the box. I also have heard that they have a weird stumble, not easily cured, coming onto the the primary circuit from the idle circuit.

I own an earlier model Speed Demon and have not used it yet but I will be looking inside it before I do. Let ya know if its chippy!

I wish now I had bought a Holley 4150HP carb for $200 more.

Kitz

I run a box stock Holley 850 4150 so I can't comment on the ins and outs of Proform, etc.

The experience I had was after finally getting the right torque converter, the car launched much harder than before and would behave as you describe... pull hard for a second then practically die then come alive like a bat out of hell. I found that my secondary float was set way too low... after raising it up to the sight hole that problem went away but later I added secondary jet extensions and a notched float for some added assurance....

It sounds like your problem is a momentary disruption of adequate fuel supply whether from uncovering the jets or fuel pump can't keep up or several other possibilities... if it stumbles right went you mash the gas pedal, you should have a look at the accelerator pumps as mentioned...

-Chris

Hey Smokedog, I have a 383 with specs like yours. I am running a simple Holley 4150 750 cfm double pumper that produced 500+ hp right out of the box. Clear float level plugs help with adjustments. Cleaning the needle valves is a simple task. Good luck.

The flow numbers on the new holley Hp series are way off. I have a 4781 850 holley that is old as the hills , I was looking at the new hp series carbs and the hp 1000 has the same dimentions as my old 850 why the huge increase in flow numbers. I think Holley is playing the numbers game the old bigger is better thing. A 900 hp is just a suped up 800 . No wonder the Demons are out flowing the Holley per rated size .

I have a Proform main body sitting around, FREE to anyone. But don't ever report back ot me.

Are you sure you have the right gaskets for the carb body,I have seen Holley carbs starve for fuel because someone installed the wrong gasket or installed the gasket upside down . This sounds simpe but it happens quite often. I have never used a Pro-form carb but I know of guys that are going real fast with a Pro-form carb body.

Hey, no idea anymore. I tried it some 5 years ago, fooled around with the jetting to try and make it work, but it was way out of wack. I could not tune it.