Holley carb recommendation, two hole or four hole idle?

[J Persons]

I'm pretty much settled on a 750 double pump, Holley shows models with either primary idle adjustment or another model with idle adjustment on all four corners. This will be used on a Edel Vic jr. Engine is a Dart block 363ci. I've always used just the primary idle adjustment type, is the four corner idle adjustment worth it?

[Wayne Presley]

I'd go with a Quick Fuel SS-750 AN carb over the Holley. It has billet metering blocks, billet baseplate, and every jet is adjustable. I sell them for $565, sold one last week for a 402W in a Backdraft and the guy loves it. Said the car has never run better.

[vector1]

i used a 750 holley ultra hp on a 351 crate engine and very happy. adjusted the idle eze and lowered the floats and haven't touched it. very nice features also. has the 4 corner idle btw.

[Greg_M]

Really depends on your cam and engine. IMO the 4-corner idle is used to adjust the idle mix on the secondaries if you have to open them up with their curb idle screw to compensate for too much T-slot showing under the primary idle plate due to a big cam.

Most times idle is set only with the primary throttle stop and the primary idle mix screws.

Does your car idle OK now with a 2 corner setup?

Greg

[Wayne Presley]

Originally Posted by vector1

i used a 750 holley ultra hp on a 351 crate engine and very happy. adjusted the idle eze and lowered the floats and haven't touched it. very nice features also. has the 4 corner idle btw.

Too bad the Ultra HP's cost $720, less features for more money over the annular Quick Fuel

[vector1]

Originally Posted by Wayne Presley

Too bad the Ultra HP's cost $720, less features for more money over the annular Quick Fuel

Holley Performance Products 750CFM Hard Core Gray™ with Black Billet, Aluminum Ultra HP*0-80803HB

don't know what you are looking at but here is the one i bought. well worth the money.

[Cone Basher]

I have a Holley HP pro series carb on my car which I run in Auto-x events and the only thing I can add to this discussion is if you ever want to run an Auto-X event make sure the carb you get has road race floats, I had to add them to mine. I like the Holley HP on my car but it has a milled choke horn and takes a bit of warm up before it idles well. Great performance carb, 4 corner idle, jets easy to change etc. I definitely recommend a dp carb if you are running a single plane manifold.
HTH
CB

[CraigS]

I would go w/ 4 corner idle. My friend just got one of the Holley double pumpers w/ the idle ease setup. He was having a hard time getting the idle below about 1400 as it arrived and ended up w/ some combination of changing the idle stop screws on both primary and secondary. Of course he had to deal w/ the proper transfer slot adjustment too.Needing to change the idle stop adjustments on both sides tells me it's good to have idle mix adjustment capability for both sides too.

[Greg_M]

I just dropped on a Holley 4776-7 600DP (2 corner idle) and to my surprise it runs, idles, and transition perfectly out of the box. The only change I made was to lean the secondaries from #73 to #70 to maintain 12.2 AFR at WOT to 6,000 rpm. Lean cruise is perfect at 13.6 to 14.7 AFR between 15" and 6" of vacuum. I run down the highway at 70 mph keeping mid 14's AFR for great mileage. The throttle response is crisp and hits hard when I stomp it. It can run at 1,200 rpm in 5th and pull flawlessly with moderate throttle. If I floor it at 1,500 rpm in 5th it does not stumble or bog. Pretty amazing.

Greg