Holley Decode Help Please

[Zedder]

Can anyone help me with this??? It's the carb that came on my project Z.

Holley 4776 List 5882 0473 What is this and what car is it from originally? Thanks

[VintageMusclecar]

Mark;

Not sure I'm reading your post accurately, but if the LIST number is 4776, then that is a generic over-the-counter Holley 600 cfm double pumper carb.

Eric

[Zedder]

Thanks Eric! Yes, that is the list number on the carb. Previous owner said it ran good with that one, but I didn't know what the cfm was. Take care, Mark

[VintageMusclecar]

Mark;

No sweat.

Eric

[Zedder]

Eric, other than the obvious CFM difference, is there anything else that is different between this carb and the 3910 my car would have come with originally? Also, I see I can buy a brand new Holley 750 cfm carb for less than $400...for a driver, is this a decent alternative? Thanks for your advice...you are the man when it comes to carbs

[VintageMusclecar]

Mark;

There are several differences. The PCV vacuum tube on the 3910 comes out of the RR corner of the baseplate, and the 4776 (et.a.l.) comes out from under the center rear underneath the back float bowl. Also, I don't believe the 4776 (et.al.) have the correct tube on the RF corner of the baseplate for vacuum advance/smog pump hook-up.

The biggest issue is the choke system; the 3910 uses a divorced choke set-up while the 4776 (et.al.) use either a manual, thermal or electric choke system. You can NOT change a manual/thermal/electric choke carb over to work with the divorced choke system.

As far as the new 750 for $400, it depends on which one you're talking about. I would not recommend a double pumper for this application if it's going to be a "driver" unless you're running 4.10 or more gears in the back, and even then it's "iffy". I'd much rather see a 750/780 cfm vacuum secondary carb in this instance.

If you're willing to make concessions to all the above issues, you could use a 3310 style carb on the car, but you won't have the correct choke system nor the proper vacuum port locations on the baseplate as mentioned above.

FWIW, I am NOT a fan of the newer 3310 carbs (3310-2 to present), I feel the earlier 3310's are notably superior carbs.

You can probably pick up an early 3310 (a 3310-1 would be ideal in this instance) for maybe $50-$100 off the `Bay and give it a proper rebuild. It won't be "correct", but it should function OK.

One VERY important thing to note here: Should you decide to find a used 3310, remember that the "original" 3310 "EH" carbs have NO vacuum ports at all on the baseplate. You would have to find a 3310-1 style baseplate to put on to provide the necessary vacuum connection for PCV. (The "EH" carbs pulled PCV from a 90* tube threaded into the drivers side of the carb just inside the throttle lever.)

You would have to run vacuum advance/smog pump vacuum to the port located on the passenger side of the primary metering block on a 3310 as there is no tube on the RF corner of the baseplate.

I think that covers the basics. If there's anything else you need to know, just ask.

Eric

[Zedder]

Damn Eric! I bet you have forgotten more about carbs than I ever knew Thanks very much for the detailed response...I really appeciate it!

[VintageMusclecar]

Mark;

Again, no sweat. There were a lot of bases that needed covered, I didn't want to risk leaving any important info out.

Eric