andre77

I'm little confused. Which is the best carb for a zz4(355hp)? I was all set to purchase the edelbrock 750 but I read that it is for a 402 cubic inch or larger. Now I'm worried that this is too large for my zz4. I don't care at all about gas mileage but I don't want to bog down at wide open throttle. My vette will have dynomax headers, chambered exhaust, th350 and 3:70 gears. I must decide soon. thanks

PS the car is used to mess around on nice weekends, not really for the track. :cool:

Paul 73 Coupe

I started out using a Holley 600 then tried a Holley 750. I never could get the 750 to run right on my car but I know others did. I went back to the 600 and dont see a reason to move up till I am making more power.

Matt M

I'd run a 650 with that motor. Not too big, yet big enough to work if you put in a bigger cam and do some head work. 650's will support over 400 horsepower.

Matt

DaveL82

I like the stealth look on my 80 so I run the stock L82 dual snorkel air cleaner. Because of this I'm limited to two styles of carbs becuase they are the only ones that work with the stock air cleaner from my old L82 motor.

The ZZ4 I have in there now makes the carb sit a little taller with just enough room.

I've run the stock rochester (edelbrock sells the rochesters new!) and this carb ran great and rochesters flow better than 750 cfm when needed.

I've also run the Holley list 6210 which is a direct rochester replacement from the early 70's. This carb has internal float adjust and the fule inlet is in the same place as the rochester. Carb is a spreadbore 650, but the real kicker is that its a double pumper.

Still at the end of the day, the rochester gives the best performance with no fit or tuning issues.

I would go with the edelbrock rochester unit, not their carter type.

Dave

andre77

Which do you recommend? Do they bolt right on? :confused:

andre77

davel82, what model number was it? :confused:

Alwyn678

I am running a holley 750 and I love it....I replaced my edelbrock 600 when I pushed the horse power up..I may be over carbed but it runs awesome and does not bog at all...But IT DOES KICK IN quite well :eek:

Lt1er

The edelbrock 750 will run fine. I never have run a 600, but it works fine on my friends mild 355

Barry's70LT1

Hi..
I have a Holley 750 DP on mine. It works great. I did have to do some tuning.
I tried a 600 on it once and it was terrible. No power at all. The bottom end
was about the same, then when the rpm's came up, the engine fell over.
I put the 750 back on and it felt like an added 100 HP.
Barry

DaveL82

If your looking for the edelbrock/rochester part number I don't have it. I would suggest contacting edelbrock directly and they will give you a match.

compuvette

The part number for the Edelbrock qjet replacements depend on what you had before:

4MV 66-73 750cfm-1901

4MV 74-78 750cfm-1902

M4M 75-85 795cfm-1903

M4M 80-89 795cfm-1904

850cfm w/electric choke-1910

Hope that this helps. If you need more info go to Edelbrock.com and look at the carburetors.

Mack

The General Motors Installation and Service Manual for the ZZ4 recommends a 750 cfm Holley or a 795 cfm Q-Jet.

The Q-Jet is P/N 17066422 which I think is an Edlebrock #1904 M4M. They say you should change out the secondary metering rods to "AH" (P/N 7033812). Wiring harness P/N 12085480 is recommended for the electric choke. They also say that this carb requires special mounting bolts, two each P/N 9419047 for the front and two each P/N 9440181 for the rear. I used the Q-Jet & I like it fine.

They say a 750 cfm Holley with mechanical or vacuum operated secondaries is recommended for the H.O. 350. The "Double Pumper", P/N 0-4779 is said to be a good choice for mechanically operated secondaries. P/N 0-3310 is for vacuum secondaries. They say stock jets should be o.k. I think those are Holley part numbers. The book says these carbs come with manual chokes and you can use P/N 45-223 for 0-3310 or 45-224 for 0-4779 to convert to electric choke.

For automatics, a TV throttle cable kick-down bracket that mounts to the two rear bolts on the Q-Jet is P/N 22504927. A throttle/transmission kickdown cable bracket for the TH-700R4 is Holley P/N 20-95.

They say to use double throttle return springs for either carb.

I'd say you ought to use this info as a start point for anything you do because I'm not sure if the part numbers have changed and I didn't use a Holley, so am not sure that the info from the book is correct. Also, I've got a 4-speed, so there may be some changes involved in a car with an automatic.

As far as which brand to use, I think that's mostly personal preference. We've already seen a bunch of "discussions" here about which is best. :D

Let us know what you end up with and how you like it.

74Vetteski

I used to run a holley 650 with my ZZ4. Never had problems. I recently changed to a 750. I have never been able to get it right. I'm always sputtering at higher rpms (3750 +). I'm not sure what the problem is. It does it regardless if I'm at operating temp or not. I'm running an MSD 6AL and it seems fine. Any suggestions welcome. I'm thinking of going back to my 650.

andre77

Thanks for the advice. I've narrowed it to the holley street avenger 670 or the edelbrock 750. I sure wish someone had this setup with an auto zz4 so I could compare. Chris(74vette) has the 750edelbrock and likes it. But his car is a 4spd. :confused:

mountainmotor

The Holley list # 3310 750cfm Vacumm secondary would be perfect for your motor.$229.00 from Jegs.You won't be dissapointed!

0Mike69@ECS

Thats what I'm running too! Runs great and I havent touched the Carb since we dropped it on top of the motor 3 years ago! :yesnod:

andre77

mike69, is your car manual? I'm worried it won't be the same for an automatic. What about the electric choke? The model you mentioned doesn't have it. Did you add it or skip it? and is it a big deal (choke)? I rarely use the car in the winter. thanks :confused:

0Mike69@ECS

My car is a 4 speed, but I have seen the same carbs on auto/zz4 cars (although not an auto vette with a zz4) My choke is Manual but I am considering swapping it over to an electronic. I havent used it since my choke cable tends to bind a little bit and it's simply easier (right now at least) to hold the throttle while warming it up. I know you can purchase a electric choke kit for the switch from Summit or Jegs. One of these days I'll get around to it!

mountainmotor

For the 3310 you can get 510-45-223 electric choke kit for $42.99 or you can buy the 510-0-80508s that comes w/electric ckoke for$239.99.
Even at 15 degrees ambient a 3310 will start a motor w/o a choke.Just pump it a few time then crank.Don't bust off? Pump it a few more times then 1/4 throttle and crank.
They have vacumm secondaries which is to an extent more desirable for an automatic car.

andre77

Apparently GM and Holley aren't on the same page. GM recommends a 750 holley for their zz4, while Holley recommends a Holley street avenger 670 for the zz4. Go figure :crazy: :crazy: :crazy: Why would Holley recommend a smaller carb? :confused: