tuning a holley for 4x4

[bluebronco69]

i was reading the tech article about rebuilding the holley carb for some off road use, and i understand the vent tube part, but what is the vent whislte, piece they were talking about or he said you can also use a vent screen what are those? and waht are the differneces? also which is better and where do they go/ is one easier to install
thanks

 

[braxton357]

Vent whistle is just what the pic shows. The plastic white piece. If your carb is newer it's probably already there, it's to help keep fuel from dumping out the vent. I've never seen a vent screen but it's purpose is the same. I would go with the whistle for the sole reason of that's what holley is using now and that's what racers/carb builders use as well.
FWIW, no matter what you do to it, the holley is never going to be as good as the stock motorcraft carb offroad.

 

[bluebronco69]

ok cool, ya right now i am running a holley 2bbl it is like a stock clone or replica kinda, it works ok off road but not on too extreme of angles, so i was hoping to get a but better performance out of it and haveing a 4bbl too
thanks

 

[braxton357]

I've also heard of people lowering the float level ~1/2" below the sight bowl and lowering the fp to ~3psi. Should help to keep from flooding. Good luck with it.

 

[ken75ranger]

A 1/2 low might be a little too much. Definately go lower than the bottom of the sight plug though.

 

[BUCKETOBOLTS]

A good rule of thumb for adjusting floats on a holley is to move the adjusters by the flats on the nut. One or two flats at a time till you get your desired result.

 

[Mikey]

If I remember correctly, the whistle vent only works on center-pivot bowls, not on the better-for-off-road square bowls. Hence, the screen.

 

[braxton357]

If I remember correctly, the whistle vent only works on center-pivot bowls, not on the better-for-off-road square bowls. Hence, the screen.

That's correct, but the article also shows how to use the whistles with side hung floats--just shorten it.

 

[BUCKETOBOLTS]

I shorten the whistle on all my center hung carbs anyway. This really helps control slosh and unwanted fuel dumping out of the vent in to the venturies. You can also pull the factory short vents out of the top of the air horn and replace them with longer ones made from steel brake or fuel line. I made one similar to the Truck Avenger for mine.

Also replace the needle and seat with the spring loaded offroad needle and seat from Holley.

 

[Mikey]

On the vent, if you want to go cheap, you can tie the two vents together with a rubber hose that you slice a bit off the top of the bend creating a hole.

How well do the spring-loaded needle/seats work? I've heard mixed results.

 

[BUCKETOBOLTS]

I'm satisfied. I believe my carb will hold its own with FI anyday. Not saying it won't fload, just I haven't found an angle extreme enough too.

 

[TJK74]

On the vent, if you want to go cheap, you can tie the two vents together with a rubber hose that you slice a bit off the top of the bend creating a hole.

How well do the spring-loaded needle/seats work? I've heard mixed results.

The spring loaded needle and seat work well and are a must add to get the Holley to run well especially in the bumpy chop. You can use rubber hose but you need to keep an eye on it cause most rubber hose or vac line tend to deteriorate with being soaked in fuel and constant heat. We would run Vac line on my buddies late model stock car but it was changed out quite frequently. I run the brake line on mine it a bit more work but well worth the piece or mind

If a holley is totally dialed in it will run perfectly on par with the q-jet and stock motorcraft 2V. but yes I agree the stock 2V is the best no hassle carb since you can just run it as is it

A fuel regulator is also key to keep your pressure in check since most standard holley's are happy at 4psi to 6max

 

[bluebronco69]

does anyone have the part number for the vent whistle, and the spring loaded valve and needle sets? im not sure what ones to run, or anything, it is for a holley 4160
thanks

 

[BUCKETOBOLTS]

Needle and Seat: HLY-6-513
http://store.summitracing.com/partd...400178+4294925239+4294846583+115&autoview=sku

Whistle: HLY-26-89
http://store.summitracing.com/egnsearch.asp?N=700+400178+4294925239+115+4294810447

 

[bluebronco69]

cool thank you so much i had no idea where to even look
i just need one of each of those right?

 

[broncnaz]

I've always ran into more problems with the spring loaded needle seats than the standard need seats but if your doing some high speed running they do work good but the cost just is not worth the hassle for me. If you go with them I think they are packaged 1 ea so you may need 2 packages one for the front and one for the rear fuel bowl.

 

[TJK74]

I've always ran into more problems with the spring loaded needle seats than the standard need seats but if your doing some high speed running they do work good but the cost just is not worth the hassle for me. If you go with them I think they are packaged 1 ea so you may need 2 packages one for the front and one for the rear fuel bowl.

One thing to keep in mind with them that I have learned is that just like a new coil spring breaking in and settling these things do the same. After they are installed and the float level is set re check them after some miles and banging around because the spring tension weakens a bit and your float level will increase a bit. After that they seem to stay consistant