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JLonano · 08-24-2002, 11:28 AM

A few posts back, I mentioned that I may have a "bad" Edelbrock Performer 750 Carb. I've been racking my brain on the best for my '67 400 Auto car. So far, I'm looking to eliminate a few of the persistant tuning issues in the Edelbrock version of the AFB....specifically a lack of off idle response and non adjustability of the vacuum secondary.

Pro's cons and opinions.....Jet or Edelbrock Q-jet 750cfm, 680CFM Avenger or 3310 750 Holley-vacuum secondaries. Of course, gas milage not as important as throttle response and performance. Also looking for ball park jetting recomendations.

Car: '67 GTO 400, #10 heads @10:1 compression. Headers, 2.5" Flowmaster, Performer RPM intake, RAIII cam with 1.7 Erson Roller rocker arms. Car is a bit heavy with full power brakes, A/C, Steering etc.

JLonano · 08-24-2002, 11:28 AM

A few posts back, I mentioned that I may have a "bad" Edelbrock Performer 750 Carb. I've been racking my brain on the best for my '67 400 Auto car. So far, I'm looking to eliminate a few of the persistant tuning issues in the Edelbrock version of the AFB....specifically a lack of off idle response and non adjustability of the vacuum secondary.

Pro's cons and opinions.....Jet or Edelbrock Q-jet 750cfm, 680CFM Avenger or 3310 750 Holley-vacuum secondaries. Of course, gas milage not as important as throttle response and performance. Also looking for ball park jetting recomendations.

Car: '67 GTO 400, #10 heads @10:1 compression. Headers, 2.5" Flowmaster, Performer RPM intake, RAIII cam with 1.7 Erson Roller rocker arms. Car is a bit heavy with full power brakes, A/C, Steering etc.

ponchopete · 08-24-2002, 09:04 PM

It's fairly difficult to beat a good tuned-up 3310 for a relatively mild street car. I know the Q-Jet guys will disagree, but since I don't have the foggiest idea how to work on a Q-Jet, nor do I want to know, my vote's for the Holley! I suppose the Q-Jet's complexity is what actually lends it to being a good street carb, as it features more refined metering circuitry, and seems to have more adjustments for extremely fine tuning. Of course, what this means, is that for the novice carb tuner, it's phenomenally easy to screw up the tune on a Q-jet. [img]smile.gif[/img] The Holley carb is exceptionally easy to tune, easy to rebuild, has great throttle response, and not too bad on fuel efficiency either when you keep your foot out of it.

shovelrog · 08-24-2002, 09:56 PM

Although I prefer a Q-Jet I also have a 3310 It provides strong smooth fool proof performance.Without re-jetting it worked fine in both my 389 and 455 out of the box.

KS circutguy · 08-24-2002, 11:30 PM

Q-jet; harder to tune, but work great, better fuel economy than a holley too.

Holley; easier to tune work great too, which ever you choose, make sure you put a quality aftermarket fuel filter in the line before the carb.. K@N has some nice ones threw Jegs or Summit..

http://photo.starblvd.net/zanko20

[ August 24, 2002, 11:32 PM: Message edited by: KS circutguy ]

Scott65 · 08-26-2002, 04:55 PM

IF you're going to change, I vote for the 3310 Holley with the metering block on the secondary side.(The metering plates are inconvenient) If you'd like some info on adjusting the secondary opening rates of the Edelbrock you have, E-mail me, they can be adjusted. I had very good luck with my 750 AFB, however as usual, results may vary.....

JLonano · 08-27-2002, 09:20 AM

Scott, what's your thoughts on a mechanical secondary 750....I know my specific car is the ideal for vacuum secondary but the old 650 Mechanical Holley I ran for a while was well tuned and ran VERY well. No bogs, great throttle response, and pretty good HP across the rev range. The only drawback was that the idle and mixture settings needed attention on a regular basis but well worth the effort. I'm wondering if a Mechanical 750 may be too much.....I know the 3310 is pretty much perfect for my combo but I thought I'd ask.

Scott65 · 08-27-2002, 11:31 AM

James,
For myself, I have no problem with running a doudle pumper on the street. I've been using them for quite a few years now, and know that they can be harder to tune on a street driven car. That said, if you feel comfortable with them, and realize, that you'll give up economy and mileage up front, then go for it. It can be done, but I think you'd end up happier with a vacuum secondary. Keep in mind this is just a generalization, as I don't know that much about your car or combo.

KS circutguy · 08-27-2002, 05:26 PM

James,
I was using a 3310 holley on my Nitrous eating 412-pontiac.

I finally bucked up and bought a Holley HP series 750 double pumper.
I picked up 2-tenths and 1 mile an hour at the strip.

Better all around performance.

And the car passed the Washington state smog test with room to spare.

And even with that fairly agressive solid lifter cam and no cats... [img]tongue.gif[/img]

I'm sure the 4 corner idle circuit is what did it, but it's $620.00 from Summitt or Jegs. [img]smile.gif[/img]

Can I get a star now? [img]tongue.gif[/img]

http://photo.starblvd.net/zanko20

[ August 27, 2002, 05:31 PM: Message edited by: KS circutguy ]

JLonano · 08-27-2002, 07:10 PM

Thanks for the advice guys. Although a double pumper sounds tempting, I think I'll go with the tried and true 3310....probably run fine out of the box with some minor tuning.

Skip Fix · 08-27-2002, 08:39 PM

My RAIV 400 dynoed within 1 hp using a well dialed in 800 cfm Q jet and a 3310 with the secondary metering block.

An even better 3310 would be like the "original" with the downleg boosters. That's why they were 780s originally and now 750s.

It sure is a pain to pull the top off my Q jet to change jets,rods, float level or power piston spring. But it sure is fun beating "race cars" with one!

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