Holley Classic vs Street Avenger

[Bruceynz]

Hi Guys,

Ok I dunno what the difference is, I have a 600 Holley classic on my car now and I have a new 770 Street Avenger in the box, I don't plan to use the street avenger as its to big at 770cfm I would of thought. I did read that the Street avenger has adjustable metering block for the secondaries where the classic doesn't and the Avenger has the quick change spring on it for vac sec, for street is there any advantage to have any of that stuff and can I change the the metering sec meter block off the avenger to the classic or is that just a bad idea, or should I consider a different carb or will the 600 be just fine?

Thanks
Bruce

 

[BudW]

Going by numbers, a 770 CFM is a bit big for a 360.
That said, it uses vacuum secondary's and because of that – it will only open as much as engine needs – so in effect, size will not (or should not) be that big of an issue (once the carburetor is set up correctly).

I should note that I am not a big fan of Holley products and never have been. I’ve worked on far too many of them.
There is one thing I will say good about them is they didn't change much over the years and they are modular in design - so a lot of parts will interchange (not that the interchanging parts are any better or are needed).

There is a strong likelihood the vacuum diaphragm assembly could transfer over from your 770 to your Holley 600 – for the sake of easier adjustability.
I wouldn’t do it, though. That would be like purchasing a new car – just to get a new gas cap for another car,

Once you get your 600 adjusted correctly – it should be fine. That said, the 770 should work fine for you, we well.


Changing subjects a bit. I played around a lot of carburetors on a 340 I had several decades ago. The carburetor I liked most was a Carter AVS (equivalent today to Edelbrock Thunder) and the older versions of the Carter Thermoquad. The TQ does not have the part throttle zip that I like, but the WOT roar can be heard a long distance away.
Now with the 4-bbl appearing fuel injection setups being reasonable pricewise – that is my new favorite (even though I don’t have one, yet).

Getting back to my point, I rebuilt and tested the AVS off of my ’70 Chrysler 300/H (440 TNT), on my 340. The primary and secondary bores are bigger than the 340 primary and secondary bores are – and testing of that 440 AVS SHOCKED me.
Just barley blip the throttle and the car jumps 30 feet. It went from a fun car to drive to a highly exciting car to drive (but really hard on tires and on the 4-wheel drum brakes I had, then).

Getting back to point, I don’t know of your 600 or 770 are square bore or spread bore carburetors. Spread bores are easier on gas mileage and easier for kids and/or wife to drive. The square bore ones jump more because more primary throttle valves are being opened at once – which might be a bit scary and/or intimidating to other possible drivers.
I suspect the primaries are bigger on the 770 than is on the 600 (but might be wrong).
BudW

 

[Bruceynz]

Hi Bud,

Both carbs are square bores so you think the eddy thunder would be a great choice? Problem down here is plenty of people know about Holley but few know about Eddy carbs.

Thanks
Bruce

 

[BudW]

I love the Carter AVS.
Edelbrock has made it better (In my opinion).

If people there are into Holley’s, then I would think that Edelbrock parts and support would not be very high. Waiting a couple of months for a part – is bad enough – especially if no one else in you region has one.

Personally – I won’t put a Holley carburetor on anything I own.

A Holley fuel injection setup – I would, depending on how they ranked with the completion.
Holley has made more fuel injection parts and setups for USA car manufactures (OE equipment), than the competition has, combined.

Carburetors are nice – but fuel injection is SO MUCH NICER.
Bud

 

[Bruceynz]

Well I have a pump in the back of the car, would be easy to put a bit of higher pressure hose on it and a high pressure pump and run efi, what is the going rate for an EFI setup?

 

[Bruceynz]

I agree EFI better but I can play with a carb in my garage! also my 600 was I dunno now under $300USD and the Holley pump was about $90USD and I am running, the electric choke seems to work well for start up too. Never gets super cold in NZ compared to USA or Canada

 

[kkritsilas]

In Canada, the FiTech Base system is ~$C1350. The better system is $C1500-1600. I think the Holley Sniper system is in that range as well.

Fuel line pressure requirements vary from system to system. I know the FAST EZ-EFI runs at 43 PSI. The FiTech is at 65 PSI. Other systems will vary in their pressure requirements. It isn't just the fuel line pressure that is a consideration, it is also fuel slosh.

It is, by far, easier to adjust an EFI system than it is a carb. Any carb. No changing jets/rods/springs that you may or may not have on hand, or even be available (like for the TQ). No jumping back and forth between setting A/F ratio and Idle speed, as one example. In most systems, if you run electric fans, the fuel injection system can also turn them off and on.

 

[Oldiron440]

I would try your other carb, its a 750 cfm vacuum secondary so its not going to be overkill....