What is some decent jetting for a holley 450cfm double pumper on a stock 12a rx7 with headers and straight pipe?

And should i disconnect one of the accelerator pumps to make it a single pumper? What size should the sprayer for the accelerator pump be?

 

Find out the stock jetting from holley (or post the list# off your choke here). You "need" both accelerator pumps!!

 

The RB Holleys are extensively modified - the various air bleeds and internal orifices are drastically altered in order to make the Holley work on an independent runner style manifold. It is far more than mere jetting changes.

Put a regular Holley on a RB manifold, and it WILL run horribly rich, and gets worse the higher you rev it. I've heard some people say that the car actually starts cutting out over ~5k or so because the mixture is so far off.

I've only ever seen one in person, and I didn't pull it apart, but I did notice that the air bleeds were drilled out so far that the inserts were practically gone.

And, it didn't have a secondary accelerator pump, despite being a mechanical-secondary carb. I actually have a pair of 450cfm Holleys that are like this, so this isn't a RB-specific modification - Holley made 'em like that.

 

pics!

 

I guess you didn't see the "only seen one in person" and "didn't pull it apart"... plus how to get pictures from before digital cameras?

What good would pictures do, anyway? "Hmm, that hole is 4 pixels wide, so that means I need to make it .093"... I think..." ?

Just buy a RB carb. They're not cheap, but they're worth it.

 

I can tune a holley to run on a rotary just fine, but most cannot and out of the box it will not. So, yeah, their are some mods done. Some of the key external mods are solving the throttle cable bracket set up, choke and most importantly the omp.

So the price difference of getting the rb carb does take care of many issues. Unless you can do some minor fabrication, tune a holley and know how they work than it is worth the difference.