Holley 600 DP setup - need pointing in the right direction!

JP. · Post by **JP.** » Sat Jul 07, 2012 6:23 am

Yess the vent tubes, and according to your picture they are cut off to. I surely think here lies the origin of your issues.
See the difference....

Holley did design it with a purpose. You can mill of the choke horn but you can't touch the vent tubes.

Left & right have the same total hight and should face outwards.
Has something to do with the airflow, disturbtion and interruption. where the air enters the throat of the carb.

Stuball · Post by **Stuball** » Sat Jul 07, 2012 8:38 am

Thanks for that.

I did some reading, and some holley carbs have removable vent tubes?

Ill have another look at mine today, hopefully they are just missing!!!
(if not, bugger!)

Stu

Stuball · Post by **Stuball** » Sat Jul 07, 2012 12:34 pm

Well I had a rummage and found some ally pipe in the garage that was a nice snug fit in the vent holes!!!
Made them so they stuck about 1 1/4" out the top with slash cut away from the carb throat.

Took it out for about a 10 mile drive.
Plugs 1, 2, 3, 4, 6 and 7 are relatively "clean" with a tan ring around the top of the insulator,
plugs 5+8 are starting to go the same way now (prob should have cleaned the soot off first!)

Looks like mixture distribution problem is now gone, thanks JP!

As for the stumbling/hesitation when applying throttle, I think I need to look at the pump nozzle sizes......?

Stu