What size Holley carb for a ZZ4

[NOVA]

I am having issues with a demon carb and am going to switch to a holley can anyone recommend the right one for a ZZ4 motor with hedders and a MSD ignition other than that stock.
the 625 Jr Demon on there was recommended by demon but it just has lots of little issues and I am tired of dealing with it.
its the third one I am done Jacking with it.
Anyone?
Thank You.

[68Formula]

Either a 600cfm Vacuum Secondary or the Avenger 670cfm. If you're going to buy new, I'd probably lean toward the Avenger.

[72nova]

I have a 750 vacuum secondary on my zz4. Mine also has the hot cam package in it though. But mine runs great with that carb. It seems that the motor is very picky about adjustments though.

[NOVA]

I think I'll try the Avenger 670 cfm Thanks for the feedback.

[quote=amcmike]Either a 600cfm Vacuum Secondary or the Avenger 670cfm. If you're going to buy new, I'd probably lean toward the Avenger.[/quote]

[Tech @ BG]

Nova,

Not sure who recommended a 625 Road Demon Jr. on a ZZ4, but that carburetor is not calibrated or designed to work on an engine like that. We offer specifically calibrated 650 Speed Demon carburetors for the ZZ4 crate engines, and would not have recommend a 625 Road Demon Jr. on that type of combination.

[NOVA]

Nova,

Not sure who recommended a 625 Road Demon Jr. on a ZZ4, but that carburetor is not calibrated or designed to work on an engine like that. We offer specifically calibrated 650 Speed Demon carburetors for the ZZ4 crate engines, and would not have recommend a 625 Road Demon Jr. on that type of combination.

Tech@BG,
Thanks for replying to the post,couple things,first yes someone did recommend it over a yr. ago I do not remember a name but they said it would be sufficient etc,I spoke with a southern dude who was very nice and welcomed any questions, as far as the customer service went that part was very good.

Secondly as the post says it is little things the first two leaked fuel right out of the box? and all of them I have a hard time finding a base plate that works and fits around on the carb there seems to be a cotter pin that sticks out and does not allow the base plate to fit,maybe the demon air cleaner bases are the only ones that work I dont know?

I'll tell you what I will do,you send me the correct carb YOU recommend (650 calibrated carb?) and I'll switch it and send in the 625 demon,also help me figure out an air cleaner for this and we are good to go.

I will work with you if your willing to work with me I'll give it another shot since you replied to this post,this is about as fair as it could be.

Regards......NOVA

[Tech @ BG]

Being a manufacture all sales go through our distribution network, who did you purchase the carburetor from? We may be able to help you with something. Our Air cleaner assemblies are setup to clear the choke housing without any modifications.

[NOVA]

I sent you a PM.
...... NOVA

Being a manufacture all sales go through our distribution network, who did you purchase the carburetor from? We may be able to help you with something. Our Air cleaner assemblies are setup to clear the choke housing without any modifications.

[Tech @ BG]

Nova,

You never responded to the last PM we sent you.

[NOVA]

BG Tech, so can this 625 be fixed or calibrated like a 650 for my ZZ4'S?

[Tech @ BG]

BG Tech, so can this 625 be fixed or calibrated like a 650 for my ZZ4'S?

Unfortunately not really, by the time you purchased the proper metering blocks and components, and did the necessary machine work to convert from a Road Demon® series carburetor over to a Speed Demon® series it would not be cost effective. They use different boosters, metering blocks, and baseplates between the two series.

In our testing, the 650 Speed Demon® Crate engine carburetor actually gave better overall numbers, and performance. We offer them with mechanical secondary’s (P/N 1282010CZZ4) for manual transmission equipped vehicles, or vacuum secondary’s (P/N 1282010VCZZ4) for cars with automatics.

[NOVA]

PM sent to you.

Unfortunately not really, by the time you purchased the proper metering blocks and components, and did the necessary machine work to convert from a Road Demon® series carburetor over to a Speed Demon® series it would not be cost effective. They use different boosters, metering blocks, and baseplates between the two series.

In our testing, the 650 Speed Demon® Crate engine carburetor actually gave better overall numbers, and performance. We offer them with mechanical secondary’s (P/N 1282010CZZ4) for manual transmission equipped vehicles, or vacuum secondary’s (P/N 1282010VCZZ4) for cars with automatics.

[NOVA]

pm sent to tech?

[JEFFTATE]

I work at a Chevy dealer.
The ZZ4 was tested with a 750 Holley.
The ZZ4 "turnkey" package comes with a 750 Holley.
I'm not saying this is necessarilly the "best" for the application,but thats what the Chevy / GM Performance Parts people used originally when developing the ZZ4 crate engine and thats what was on it when it was dynoed at 355hp. GM may have just used or recommended this carb because of some corporate politics.
I would listen to the guys at Barry Grant.
They know what they are talking about.
I have known literally dozens of people that have followed there recommendations and have never had a problem with there carbs. And have gotten better performance and even better mileage.

[NOVA]

Thats why I asking them what I can do to the 625 to get it right, I am sure it is the same housing.
I am waiting for them to reply to this so I can get it fixed?

If this 625 cannot be fixed, what is the part number for the 650 that they recommend??
\DEMON TECH TO THE HOT LINE PLEASE!

I work at a Chevy dealer.
The ZZ4 was tested with a 750 Holley.
The ZZ4 "turnkey" package comes with a 750 Holley.
I'm not saying this is necessarilly the "best" for the application,but thats what the Chevy / GM Performance Parts people used originally when developing the ZZ4 crate engine and thats what was on it when it was dynoed at 355hp. GM may have just used or recommended this carb because of some corporate politics.
I would listen to the guys at Barry Grant.
They know what they are talking about.
I have known literally dozens of people that have followed there recommendations and have never had a problem with there carbs. And have gotten better performance and even better mileage.