Quadrajet M4ME compared to Holley 4160

[81_Z28_NC]

Just been reading up on some carbs and was just curious what are the major differences between these (2) carbs besides the following....both are 750 cfm, one is spread bore the other square bore, both have electric chokes/electric choke capabilities (holley is manual choke but can be converted to electric with appropriate kit), both have vacuum secondaries. Besides the Holley being designed for "universal" applications are there any other major differences (performance etc) ?

FYI I have a Holley 4160 0-3310 (currently upgrading to electric choke) and wanted to compare it to the standard Qjets. Thanks.

[onovakind67]

The Quadrajet M4ME has dual boosters in the small primaries for improved light throttle response, secondary accelerator circuits, and demand controlled secondaries that do not depend on flow through the primaries to open. Ant they are ugly, too.

[81_Z28_NC]

Is it more accurate to compare to the 4MV ? Since the 4ME (and 4MC) appeared on the beginning of the de-tuned engines ?

[onovakind67]

They're pretty much all the same. You will find different bleeds, rods, jets, springs, etc. but the basic operation is the same.

[81_Z28_NC]

They're pretty much all the same. You will find different bleeds, rods, jets, springs, etc. but the basic operation is the same.

Thanks...it looks like the Holley will never meet the throttle response or MPG of the QJET ?

[Damon23]

Ah, Ken. Any progress on the oil issue with PCV? You know i'm on pins and needles about that right?

I'll probably end up changing out my carb eventually. I've been thinking about it but for right now, and the budget I have to stick with what I have seeing I had it rebuilt already.

[81_Z28_NC]

Ah, Ken. Any progress on the oil issue with PCV? You know i'm on pins and needles about that right?

I'll probably end up changing out my carb eventually. I've been thinking about it but for right now, and the budget I have to stick with what I have seeing I had it rebuilt already.

Thanks for the concern Damon, I'll keep you posted

I actually was thinking about your carb today....I know you just had it rebuilt and I am guessing it is a M4MC since it is a 79. With you changing out to headers and swapping the intake do you plan on converting the hot air choke to an electric choke ? Just some thoughts.

[ZS10]

The Q is a little more sensitive to vacuum and needs a stronger signal to be happy. The holly can be tuned to compensate. A Q jet will likely give you better mileage.


For a driver a Q jet is very tough to beat. For performance a 3310 with a HP or Proform mainbody works very well.

[z28cp]

I do use the 3310 Holley myself. Having said that, all else being equal, the Q-jet will beat the Holley off the line every time, do to the higher airflow velocity thru the smaller primary venturis. This provides better off-idle response, and helps force the mixture into the cylinder more efficiently at lower rpm's. And, if you keep your foot out of it, the Q-jet should indeed get better mileage.

[Bikefixr]

Q-jets are very sophisticated carbs. They can be tuned easily..but since Holleyhas the lions share of the performance market, parts and advice are easier to find. I have a JET built Rochester and lemme tell you...this thing drives like a fuel-injected car. Wne I rebuild the 396 in y Camaro this summer, I am sending my prized NOS date-coded Rochester to JET for the tune and modifications. Q-jets do have 1 serious problem. They leak internally. The main-well has plugs in the bottom and the plugs start leaking...right into the manifold . Epoxy fixes that. I have Holleys, too. They work great. But they are very sensitive to dirt and the floats and needle-setas have always been a pain. They stick open or closed, float levels get of of whack for no reason. The off-idle stumbles can be vexing as can idle to mid-range. Bottom line, whichever you use, learn how to tune it properly.

[81_Z28_NC]

Everyone...thanks for the good info.