I'm not sure what kind of Holley but I know its from a 75 truck # on the front D5TE 9510. I'm thinking 4350, it' s install on 302, there was a severe case of over fueling when I purchased the vehicle, after tweaking it burns clean now. I can't get the secondaries to open with the air cleanner on. It will try to open slightly at WOT ~6000 RPM. I've removed the spring and its a little better but it won't open with the air filter on. Any Ideas on the CFMs carb and is good for a 72 mustang with a 302 with large cam and intake.

 

Hi,

How are you determining that the secondaries are not opening?

Are you "winging" the engine up to 6k RPM while the transmission is in park or neutral and watching for the secondaries to open?

The reason I ask is because many folks who own a vacuum secondary carb don't realize that this won't work. This style carb functions on engine load measured thru a vacuum source. If there is a very light load on the engine the secondaries won't open at all(or very little) even at WOT/max RPM.

If this is not your problem and if fact you know the secondaries are not opening when under a load then I would check for a linkage problem or maybe one of the tiny capillaries in the carb body is stopped up not allowing the vacuum signal to be sensed.

Hope this helps and good luck,

 

Is this carb any good for a 302 with large cam and Elderbrock Streetmaster intake, in a mustang. I think it's from a 75 truck with a 460ci I was wondering if it needs to be rejetted.
Thanks

 

Yes you're right I was trying from the seat of pants in park, I'm going to run a vacuum gauge in the cab to see what's going on.
Thanks

 

Hi,

Sorry I can't give you any application data but I can tell you it is a 600cfm carb. Also,

the Holley renew(rebuild) kit # is 3-1012,
Main jets are 122-612,
Power valve is a 125-206,
Accl pump discharge nozzle is an .025, and
it came stock with the plain colored secondary spring.

Good luck,

 

Looks like it has 61 jets in the front( the 2 means that they are exactly 61's. Most OEM Holleys use jets with the 2 on the end due to emmision callibrations so that they are all the same when new). I would bolt it on and try it. It may be a little lean, but not by much. It should be close enough to run pretty decient. I run 62 jets on a fairly stock 351 so yours should be close.
Jimmy

 

Make sure that you put the spring back in first, of it will bog really bad when you open it up. It should start coming open around 3000 rpm or so. You may not feel it open, they open kinda slow. You may have to run it with an open element air cleaner the hear if they are opening. Sometimes on smaller engines like the 302, you will have to put a lighter spring in it. What color is the spring that you removed? It should have a paint mark towards the top of it. If it doesn't, then it is the natuaral spring which is about in the middle. Holley has a spring kit with all of the different springs and a chart that tells when they will open on different sized engines.
Jimmy

 

Thanks for all the help turns out I found a bad vacuum leak on primary thottle shaft where the choke bolts onto. When I took it apart I found the nylon bushing (bearing) was missing, I would fuel leaking from the shaft with the engine off and moving the thottle, giving it fuel. So I think I found my Problem with tunning this carb. I ordered a rebuild (quick kit), and secondary spring kit from summit today.

Thanks again!