Low RPM....Good / High RPM....Not so good??

KANE · Apr 2, 2007

So I've been taking advantage of the nice weather and driving the bugs out, but one just won't go away....

351 with a holley carb. Low to mid rpm is perfect. When I really lay into it, it starts to fumble, like it has a rev limiter. A couple of times it pulled without a problem, most of the time it stumbles.

My question is how can I tell if the vaccum lines are correct? I can see 2 noticable in the front of the carb, I tryed switching the bottom(which was capped) with the top. It seemed to idol better, but seemed worse when I layed into it.

I've heard distributer, fuel pump, or maybe just adjustment??????

Any help is always appreciated !

Thanks,
Mike

76Broncofromhell · Apr 2, 2007

It sounds like you aren't getting full advance out of the distributor. Usually the upper shaft will get frozen to the lower one.

I had this happen on my GPW. The upper shaft was frozen to the lower so there was no mechanical advance which caused a higher RPM miss (2400+).

I would either take the distributor apart or buy a new one.

On the carburetor end of it, hook it to the nipple on the metering block, not the baseplate.

ugly74 · Apr 3, 2007

mine did the same kindof thing, and it was in fact, the distributor.

KANE · Apr 3, 2007

What would you recomend for a new upgraded distributer and who to get it from? What kind of job is it to do?

Thanks again!
Mike

broncnaz · Apr 3, 2007

What model of holley carb? It may just be the secondaries kicking in too soon. Check the float level in the rear fuel bowl if its to low you could just be running out of fuel when the secondaries are open. actually check the primary fuel level also as it can cause the same problem.
For the dist just make sure the advance is working just remove the cap and turn the rotor CCW if it doesnt turn its frozen and you need a new Dist if it moves and snaps back its good your problem is somewheres else ie probably carb

BYUBRONC · Apr 3, 2007

I would try the Pro-comp HEI. Coil built in. Works GREAT.

KANE · Apr 3, 2007

Broncnaz - I don't know exactly what model Holley, but if you know where the model number is.....I'll look and let you know. How far around CCW would the rotor turn - I tried but it only turns about an inch or less and springs back. What do you think that means?

BYUBRONC- Where did you get the pro comp and how much?

Thanks,
Mike

broncnaz · Apr 3, 2007

The model number on holleys is stamped on the airhorn with the aircleaner removed you should be able to read it. Your advance is working properly they only move about a 1/2" max usually.

1sicbronconut · Apr 3, 2007

I'd use nice orginal Duraspark. There are some good write ups about the swap and painless has a nice loom out also.

BYUBRONC · Apr 4, 2007

KANE said:
Broncnaz - I don't know exactly what model Holley, but if you know where the model number is.....I'll look and let you know. How far around CCW would the rotor turn - I tried but it only turns about an inch or less and springs back. What do you think that means?

BYUBRONC- Where did you get the pro comp and how much?

Thanks,
Mike

I got mine from a friend. JBG's got them for 150 bucks. Solved my problem, would run great except if you got in it from a slow idle.

KANE · Apr 6, 2007

OK...I've got some #'s off the Holley carb - on Pass. side secondery: 4505b - on front (butterfly) : list 6819 0522 - Hopefully that makes sense(thanks Broncnaz)

Thanks,
Mike

KANE · Apr 6, 2007

Wanted to let you know it's FIXED!!!!!! The timing needed to be advanced - a little turn and she's pulling to redline!!

Thanks for the help!
Mike

Low RPM....Good / High RPM....Not so good??

KANE

Sr. Member

76Broncofromhell

Bronco Totalitarian

ugly74

Bronco abuser

KANE

Sr. Member

broncnaz

Bronco Guru

BYUBRONC

Full Member

KANE

Sr. Member

broncnaz

Bronco Guru

1sicbronconut

Bronco Guru

BYUBRONC

Full Member

KANE

Sr. Member

KANE

Sr. Member

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