I have a '72 with a 350, 4 speed, 750 Holley carb. When I get on the gas good and get the car up to around 3500 to 4000 rpm it feels like it is not getting enough gas.

So I took a look at the carb, to see if I could spot anything. This is hard to explain so bear with me. I noticed that if I push on the throttle trigger as far as it will go so that the carb is "wide open" that secondary throttle plates dont open.

It appears that the rod connecting the primary trigger to the secondary throttle plate trigger is not capable of moving the secondary trigger. I am able to manualy open the secondary throttle plates by pushing on both triggers at the same time.

Any suggestions on how to fix this problem?

|UPDATED|8/22/2003 3:31:45 PM|/UPDATED|

Is this a vacuum secondary carb? They don't normaly open when you gas it sitting in the driveway. As long as the primaries are openning all the way you should be able to easily move the sec, if not , then something is sticking. Does the throttle open the primaries when you step on the pedal?

It is a vacuum secondary carb, I looked it up at holley.com. It is the 80508S.

The primaries do open all the way, but if its a vacuum secondary why is there a rod connecting the primary and secondary triggers?

I'm not sure what rod you are referring to but it may be the one that keeps the secondaries from openning unless the primaries are open all the way.

I'd have to agree with Brian, I doubt you're having a problem with your secondaries opening. If the engine is leaning out at high RPM's (which is what I think you mean) then the secondary throttle plates opening would actually make the problem worse.

I'd have to think about it a little further but right off the cuff I'm wondering if the fuel levels in the bowls are correct. A weak fuel pump is also possible.

Can you describe the problem further?

From the little I know about Holley carbs I seem to remember there are secondary jets that can be changed for larger or smaller as required. A Holley strip kit should be available and there should be several jets in the kit. Try going up and down in size. Often, an over rich condition can bog the car as well.

Alex

|UPDATED|8/29/2003 3:33:24 AM|/UPDATED|

I like changing over to high volume fuel pumps. This may not be your problem at all but I've never installed a high volume fuel pump on a car I was familiar with and not had an obvious improvement at higher engine speeds.