I have the above combo running very good. I am running the Edelbrock at close to it's richest settings (rod & jet) and it is running clean and has no stumbles, flat spots or surges at part or full throttle. If anything, it feels like it may want a bit more fuel when stomping on it at around 3K RPM.
My question is this. I have been thinking about moving to a Holley 650 or 700 double pumper w/mechanical secondaries to gain more power or at least the kick in the seat when the the secondaries open up. But I don't want to give up driveability since this Edelbrock seems to be working well. This combo is good to 6,500 RPM or so, but I don't usually wind it much past 6,000. Do you think the Edelbrock 600 is holding this combo back? If it is, would the 650 or 700 double pumper w/mech secondaries be a good choice? I'm trying for most bang for my buck here. I don't want to swap carbs if it's not a big gain in power (at least something I can noticably feel).
I don't take the car to the track much, so this change would mostly be for street driving. Trying to use my limited "fun money" wisely. If changing to the Holley, what would be a good starting point be on jetting?
Thanks for any opinions/suggestions.
Dec 11th, 06, 01:27 PM
My .02 here. I think you would notice performance from a 750 Holley. You may notice a more crisp response with a 650 but its hard to try to tell people this. I would not go above a 750. For what you are saying about driveability, I would go with vac secondaries. Sounds like you are running a dual plane manifold . At your elevation, I would begin jetting out of the box and read from there. I have 3310-4 and run 68 / 76 with 65 power valve. I have run it from 0 sea level to 6k ft with some slight over jetting but its only tempoary as I come back to 3500 altitude as home base. I run the Airgap rpm, dual plane.
Dec 11th, 06, 02:03 PM
I had a edelbrock 1406 on my 69z28 350/330ho motor with an edelbrock performer rpm intake m-22wr and 4:10 gears. it has 9.1 compression and vortec heads with the voodoo 268 cam also. I newve could get a slight miss out of my edelborck at 3200 rpm. I fattened it up as much as I dared and got most of it out. I switched to a 650dbl pumper and like it much better. The electric choke doesn't work as well but it performs alot better at the strip. I am considering stepping up to the 750 main body or an hp carb. Good luck with your choice.
Dec 11th, 06, 04:02 PM
Here's my 02¢
There is no real difference in performance between the Carter AVS (AKA Edelbrock) and the Holley. Both have been around for decades, and there are no unfair advantage of one over the other. The Edelbrock is strictly vacuum controlled so it offers a smoother transition from idle to off idle to wide open throttle; with tuning available to modify the accelerator circuit, main jets emulsification, everything just like the Holley (which does offer a more brutal mechanical advance as well as vacuum).
I learned on the Holley system and use only Holley's because I have every thing made to tune a Holley. If you have invested time to learn the Edelbrock and have invested money on rods and jets then I would stick with it and acquire another larger Edelbrock carb. I think it is the cfm you need not another system.
Dec 13th, 06, 09:13 AM
Thanks for the advice guys. From what I've read, a 750 might be just a little too big on my 355 but it might be worth a try running one with vac secondaries. I have have good luck with Edelbrock and know how to tune them so I might just end up staying with one. Guess I might have to buy one and try.
Dec 13th, 06, 10:01 PM
My father in law is selling a 750 edelbrok thats in great shape. He wants $100 bucks for it. E mail me if you are interested. firstname.lastname@example.org He lives in Stockton and works in Sunnyvale so its pretty close to you.
Dec 15th, 06, 08:42 AM
a 750cfm edelbrock is not equal to a 750cfm holley DP in terms of real flow (one is dry flowed, the other wet-flow tested), so you would do fine with the 750 or 800 cfm edelbrock properly jetted.
If you instead go to a Holley, forget the double pumper if driveability/ economy is a concern. Go with a 600-700cfm vacuum secondary holley. You give up little in performance, but gain a lot in driveability/ economy as I found out for myself.
Dec 15th, 06, 10:13 AM
What kind of transmission are you running? That will have a big impact on your choice.
Dec 15th, 06, 02:49 PM
Running a Muncie M-21 and a 4:11 Gear. Cruises around town in the 3,000-3,500 RPM range. Forget about the highway. I don't take it for long highway drives.
Dec 16th, 06, 03:26 AM
I've had both an edelbrock 600 and 750 on a pretty hot 327 a few years ago, and then put a 600 Holley with vac secs on. The Holley flat out killed the Edelbrocks in performance, especially the low end. VERY snappy. The Eddy's are nice if you just want something to run decent out of the box with low maintenance, but if you want pure performance with good drivability, I don't think you can beat a Holley type vac sec carb. There is a reason so many higher performance street and race cars use them. They flat out work!
Dec 16th, 06, 08:48 AM
Ive never taken the time to tune an edelbrock but out of the box the best carb ive ever had was a downleg booster holley dp, flat out killed the VC 750 and edelbrock.
Dec 16th, 06, 09:06 AM
" There is a reason so many higher performance street and race cars use them. They flat out work!"
And I though the choice of components had to do with purchasing agreements and being able to meet the delivery requirements. As you may know Chevy used Carter AVS and AFB carbs for years as their choice for a high performance four barrel (they made the Rochester 4GC in house along with the Q-Jet). By the way Chrysler chose the Carter AVS for the Hemi and the all of their hot little cars using the Holley only for the six pack (Carter didn't make a high CFM fully adjustable two barrel). I can remember back when these cars were new; many a weekend evening "discussing" the virtues of which was faster the "bird", 'cuda, GTX, Challenger, Duster; or the Chevelle, Camaro, Nova. (everyone but Ford fanatics agreed the Mustang and Maverick belonged back on the ranch).
Dec 16th, 06, 08:20 PM
I have several books on chevy performance and also some of David Vizards books. I know that the 302 Z-28 motors (including the cross ram manifold) used Holley carbs, the 360 hp 350 ci 1970 z-28 motor used Holley, and I also have read all the HIGHER horsepower 396, 427, and LS6 454 used Holley (780-830 or 850) from the factory. I may be wrong on a few of these, but I am pretty sure many of the higher performance CHEVY motors came with Holleys or at least had them as an option from the factory. Again this info is for Chevy motors only. I know Pontiac used mostly Q-jets and maybe Carter? Not so sure of Ford and Chrysler. I also think that if you look under the hoods of carbureted motors at the track, at least 8 out of 10 will have a Holley or some "after market" version of a Holley. For example I have a Pro Systems 1000 HP on my 496. Its more or less a modified Holley. An exerpt from David Vizard's book "How to build horsepower- Volume 2" is as follows. "Without a doubt Holley's range of performance and replacement carburetors represents one of the best value-for-money performance deals in the marketplace today.......More high performance and race engines reside under a Holley carb than any other carburetor in the world. One good reason for that is results!" I would encourage anyone to get as much info as they can about any part, ask around at the track, on-line, etc...But I think that a majority of people will tell you that from research and real world experience, a PROPERLY tuned Holley will out perform a PROPERLY tuned Edelbrock. I did tons of research on this before I finally decided on a carb for my 496. I've had experience with both and the Holley won hands down. I'm not saying the Holley is the better choice in EVERY motor, but I do think it is the best for most of them. Again just my .02
Dec 16th, 06, 08:42 PM
Holley 750 double pumper will work well with proper jetting.
Dec 17th, 06, 07:57 AM
Holley 750 double pumper will work well with proper jetting.
Hey Phil I didnt know you were on here! This is the man that ported my heads great guy knows his stuff & owns a mountain motor street car!