Technical Help on my Studie 259 V-8

So I have a stock 259 V-8 in my Studebaker car. I have a 600cfm vac. secondary Holley on it and I am having a terrible time trying to get the thing right. It starts and idles very well but when I'm trying to accelerate it falls on its face and I'm talking regular driving, this is not a drag car nor do I have any expectations of it being a high performance ride. It just wants to die above 20 MPH unless you go very slowly down on the gas pedal. I was thinking the power valve or the vac. to it was the culprit, this was after playing with the acc pump and squirters. I tried various pump cams and it didn't change any thing. I've tried different timing settings and checked the (Delco) distributor to make sure it was advancing as it should-it seemed to. So does anybody have any ideas or thoughts on this? I could use some help! Normal Norman

 

have to be some holley gurus out there

 

don,t rule out ignition probs. my 58 ford ran like that and after rebuilding carb etc and ignition tune up didn,t change anything,i checked the ballast resistor as a last ditch effort and it turned out to be bad. put a new one on and the car ran great! just a thought!!
jp

 

Could it be over-carbed? The stock carb was around 400 (425?) CFM.

 

When it starts to stumble, is there any smoke? Black smoke would indicate it is going rich. A stumble without the black smoke can mean a lean condition, like the fuel level is too low on the secondary side.

If this is an old carb, it could also have the metering plate gaskets all shrunk. That can totally screw up the mixture above idle. Do you know the history on the carb?

 

If you are running full manifold vacuum advance try changing to a ported vacuum signal using the appropriate vacuum pickup on the carb. This will probably require an idle speed adjustment. With manifold vacuum on the vacuum advance mechanism the vacuum advance is "all in" at idle. Then when you accellerate and the vacuum drops precipitously much of the spark advance is suddenly removed from the distributor, causing the engine to lay down or bog.
With ported spark advance, only a small vacuum signal is present at the distributor at idle. The throttle plates are open wider and the vacuum signal increases more rapidly when the throttle plates are opened.

A 600 cfm on a 259 inch motor is probably a bit overkill (I use one on my 460 ci '46 truck) and a 390 or 465 size would probably be better. Having said that, the fact that you have vacuum secondaries means it shouldn't be impossible to get the 600 to work. The secondaries may never open fully, but it should be OK anyway.

Good luck.

 

Perhaps you should ask over on the forum of the Studebaker Drivers Club....

 

The Holley carb requires an adapter to fit the Stude intake manifold and thus twice the chance of vacuum leaks.

Do you know anyone with a known good WCFB or small CarterAFB/Edelbrock carb? Remove the Holley and adapter, bolt on the good carb and see what happens.

jack vines

 

600 holley on a 259 is larger than it needs no air speed to pull fuel its going to need larger jets to run but you would be better off with a smaller carb