Hi...

I'm totally a newbie on this forum

First of all, let me introduce me :

I'm a French Canadian, now living in France. I'm owning a 1971 Barracuda Gran Coupe 383 (matching #) The car was sold new in Switzerland, where I've bought it.

Lately, I've rebuild the engine. Beside the block, crank and rods, everything is new. The engine is slightly modifie, but still a 383.

I do have a light problem with the acceleration.
On the idle, the engine turn perfectly, but if I put the pedal to the metal, there's power, but rapidly nothing for many seconds, then it takes it rpm perfectly.

There's nobody who know's how to tune a Holley at 200 miles around me... So... Im' asking for a little help.

I've got a 670 Street Avenger on a 383 that must have around 400hp.

My psi is around 12.5, the power valve is a 65
The pump nozzle discharge is a 37 (how do I calculate a good one?)
The cam on the carb is the yellow one (how do you figure the one to use?)
The spring is the pusple one...

Where should I look? Start? For the moment

Thanks a lot and best regards from oversea











PS: There's less than 10 Barracuda/'Cuda 71 in this country

that fuel pressure seems way high to me. not sure if you are reffering to a 'bog' problem or not. why is your pressure so high?

I agree.Do you have a regulator plumbed into the system? I would set it to 6-7 psi at the carb.

When you say my PSI is 12.5. I am thinking you mean Vacuum is 12.5 inches. If that be the case, you could change the power valve to maybe an 8.5. Check float levels. Also it is a possibility that your accelerator pump is bad. Without the engine running, take a look in the throat of the carb, when you open the throttle, and see if you are getting a good shot of fuel from the accelerator pump. If need be, replacement is very easy. The information on how to perform this work, is available online if you do a little search. Do the diagnosis first.

Since the problem is from standing still or moving slowly, most likely it is accelerator pump.
As others have suggested, check to see if there is decent discharge at all. Engine off, choke open (if there's still one on there), you should see fuel out of the nozzles with the slightest movement of the throttle moved with your hand.
If not, make sure the lever is just resting on the cam at idle. Adjust with two wrenches.
According this pump cam chartat Holley's website, the yellow cam is the most agressive. Maybe best with the 50cc pump.
37 is is the size of the restrictions in the discharge nozzle measured in thousanths of an inch.
37 = 0.037 inches diameter Thats a pretty good start, maybe too big.

If you see lots of fuel, then more likely its too much fuel too early. You'll have to buy a smaller discharge nozzle or a less agressive cam. Cam changes total volume delivered, nozzles effect when the fuel is delivered. Larger nozzle lets more fuel through right away.

If the pump is leaking, you should see or feel its wet underneath.

A good book on Holley Carb is Urich & FIsher's Hollery Carburators and Manifolds, HP Books.

Are you aware of the Mopar Club in France? I have a link on my home page (click on my screen name to get to my home page). Unfortunately I can't read French but they have good racing history on the website.

Check ignition timing, then fuel pressure.

I can save you some money here.
send me tickets and directions, maybe a security detail and I will come over with a known good carb and tools.
Otherwise, it will cost more to send the car here for us to fix!!!

The 37 squiter sound and is too big start back to stock or 28 squiter. A Purple spring should be ok but make sure the carb is problem and not timing. Most 383s like in area of 38-40 degree's total timing not the Mopar bible 36 total. Is the engine a real high comp or stock ? That will detremine the timing needs