Rochester or Holley
Burning Brakes
Joined: Jul 2001
Posts: 1,160
Likes: 0
From: Ajax Ontario
Re: Rochester or Holley (Armstrong)
I won't pretend to be any expert, but you will probably get better advice if you provide full info on your engine, mods, intended use. I've been amazed at how double pumpers with mech. secondaries, can be perfect for one application and not at all appropriate for another similar displacement engine.
Safety Car
Joined: Sep 2000
Posts: 4,679
Likes: 6
From: Charles Town WV
Re: Rochester or Holley (Armstrong)
If your car is an '81 you may not have much of a choice. I believe 81's had a computer controlled rochester.
Otherwise, it's a function of what you know how to deal with and how your engine is set up. If you are running bone stock, I'd say stick with the quadra-jet. If I were running an aftermarket intake and had some performance mods, I'd run a Holley 650 DP. I've always found Holley's to be easier to deal with than quadrajets. They are a much simpler design and are cake to rebuild, re-jet, and tune, but they can be finicky sometimes.
If you know more about rochesters than use it. A Carter AFB is also an excellent carb. I just rebuilt the one on my 61 Buick last week. Edelbrock makes a pretty good (and popular) knock-off of the Carter design too.
Otherwise, it's a function of what you know how to deal with and how your engine is set up. If you are running bone stock, I'd say stick with the quadra-jet. If I were running an aftermarket intake and had some performance mods, I'd run a Holley 650 DP. I've always found Holley's to be easier to deal with than quadrajets. They are a much simpler design and are cake to rebuild, re-jet, and tune, but they can be finicky sometimes.
If you know more about rochesters than use it. A Carter AFB is also an excellent carb. I just rebuilt the one on my 61 Buick last week. Edelbrock makes a pretty good (and popular) knock-off of the Carter design too.
Instructor
Joined: Dec 2001
Posts: 153
Likes: 0
Re: Rochester or Holley (Armstrong)
stick with the q-jet unless you have enough engine mods to jutify the rest of
the changes needed to run a holley ie. spacer/adaptor. linkage, kick down , fuel line and filter. try an earlier model q-jet a non fead back type, but then you may need to change distributers since your does not have a vacume advance. thats my 2 cents :cheers:
the changes needed to run a holley ie. spacer/adaptor. linkage, kick down , fuel line and filter. try an earlier model q-jet a non fead back type, but then you may need to change distributers since your does not have a vacume advance. thats my 2 cents :cheers:
Racer
Joined: May 2000
Posts: 386
Likes: 0
From: Niedernhausen, Germany
Re: Rochester or Holley (Armstrong)
I would prefer the Q-jet most definitely. Admittedly, it is a little more sophisticated than the Holley but that also is the reason why it has a much better gas mileage and throttle response. However it can be tuned as well as a HOLLEY - if need be.
I installed one on my 72: Better throttle response, 25% less gas consumption an better cold starting characteristics.
The Holley is a muscle-car carb which was designed for easy tuning on the track - but fuel consumption never was an aspect those days.
I installed one on my 72: Better throttle response, 25% less gas consumption an better cold starting characteristics.
The Holley is a muscle-car carb which was designed for easy tuning on the track - but fuel consumption never was an aspect those days.
Race Director
Joined: Jun 2000
Posts: 10,029
Likes: 661
From: FL
Re: Rochester or Holley (V8yunkie)
I agree with Yunkie. Dyno 2000 says I got 335 HP with mods and I know I get 18-20 mpg with my Q-Jet. Just takes a little longer to tweak than a Holley but definetely worth it (Thanks to Lars. :yesnod: )
Melting Slicks
Joined: Jun 2000
Posts: 2,965
Likes: 2
From: North side of Houston Texas
Re: Rochester or Holley (Armstrong)
I had the same question in regards to our '72, but for economic reasons I decided to stick with the QJ. And I'm glad I did.
Check out Lar's papers on Corvettefaq.com on how to tune it properly. And the factory service manual will help on setting the idle mixture if it's been messed with.
My QJ's been more of a chore to set up than the Holley's I've done in the past, but it's proven to be every bit as good of a street carb now that I've gone through it.
Check out Lar's papers on Corvettefaq.com on how to tune it properly. And the factory service manual will help on setting the idle mixture if it's been messed with.
My QJ's been more of a chore to set up than the Holley's I've done in the past, but it's proven to be every bit as good of a street carb now that I've gone through it.
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Race Director
Joined: Mar 1999
Posts: 10,258
Likes: 1
From: Calif.
Re: Rochester or Holley (Armstrong)
Quadrajets are really terrific carbs. When they're properly tuned they can give you good mileage, snappy throttle response and great performance. There's a wealth of information out there about tuning them and dilaing them in and you won't have to have a huge assortment of parts around to mess with while tuning.
That having been said, the more I learn about and fool around with Holleys the more I like them. I've found them to be more responsive to tuning and somewhat easier to set up once you get them in the ballpark. But, the ballpark on the Holleys seems to be smaller--you either have them dead-on right or dead-on wrong.
Your mileage will probably vary. But I don't think you'll go too far wrong with either choice.
[Modified by The Dude, 12:04 PM 1/7/2002]
That having been said, the more I learn about and fool around with Holleys the more I like them. I've found them to be more responsive to tuning and somewhat easier to set up once you get them in the ballpark. But, the ballpark on the Holleys seems to be smaller--you either have them dead-on right or dead-on wrong.
Your mileage will probably vary. But I don't think you'll go too far wrong with either choice.
[Modified by The Dude, 12:04 PM 1/7/2002]