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By Talkwrench - 8 Years Ago
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 Quite often guys ask questions about what carb works, So I thought I would share my experience.
Disclaimer : this are my own findings and based on a stock 292 , FORDOMATIC. With pertronix ignitor 3, timing at around 12 initial, total at 36-38 and all in by 2700 rpm. B manifold port matched, 1/2" 4 hole spacer for the carb. twin exhaust through Smithys. And bum dyno.
1. Started with a 600 Holley auto choke. Fine, worked ok . I think in the end I settled on 62 jets, 10 " P/valve, blue pump cam , 31 squirter , black secondary spring . Good point seemed to always start no problems after sitting a few weeks. The 600 now sits on my 74 Cuda. changed settings of course, It works really well on that.
2. Went to a 450 Holley auto choke, supplied and rebuilt by Phil at RPM ind. with that one I settled on 58 jets, 8.5 P/valve, green pump cam, 31 squirter, brown secondary spring. Good point.. None really was about the same as the 600, the only thing is that it seemed to dry out because of the vent in the float bowl.
3. Now on an Edelbrock 600 performer 1406 [the economy one with electric choke] was originally on my Cuda. With this one the stock needles and jets with the heavy 8" springs. I tried the next up rich needles [23] but it felt very much like the Holleys - fat. I have felt a difference with the Edelbrock it seems to have much better transition and though mid range to top end seems stronger, definitely noticeable with the standard needles. It did however have a very very slight of idle flat spot, I just moved the pump jet to the nearest hole and bingo all good, I found from a standing start I can floor it and it pulls away clean, slow as slug but clean, the Holleys Mmm just . Good point, well I guess its the stronger mid range now thats important.. >>> [Also the kick down works better..??]
Because its a Fordomatic they can be a bit of a slug because of the way it works, as we know its really just a two speed. Start of in second gear and a lot of the corners - round-abouts etc your usually driving out in top gear..
The one thing that has been evident with my car is that it likes a bit fuel straight up, note the "heavy pump cams" even with the Edelbrock pump.
The Y block and Fordo - doesn't seem to be that fussy I really think that any carb from 390 to 600 CFM works ok, I haven't seen a revelation , just the stronger mid range in Edelbrock I guess.
Hope this helps someone.. 
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By Vic Correnti - 8 Years Ago
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I will add that my experience with Edelbrocks and Carters is that they stay in tune, are easy to tune, and no such thing as a fuel bowel leak. My usage is on the street as well as the drag strip and they always preformed well for me.
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By 2721955meteor - 8 Years Ago
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verrey good artical. re the ford auto, not dificult to make it start in low,go to a older motors manual ,they have good inst on linkage adjustement,after you do this giv the cevice 1 extra turn(more throtle presure). have done several with good results.will have to find a edelbrock for my ranchero 292 .
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By charliemccraney - 8 Years Ago
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I only have experience with Edelbrock and newer Holleys (Street Avenger). Of those, the Holley is my preference by far. Both stay in tune but the Holley is far more responsive and easier to tune and more tuneable. The Edelbrock is easy to tune as long as the change only requires metering jets but when it comes to actually changing the jets, the Holley is fast and easy, only 4 screws and a fuel fitting. On the Edelbrock, it's a fuel fitting, 8-10 screws (don't remember exactly), a tiny clip for the accelerator pump that is easy to loose, and i think there is also a clip for the choke - by comparison, a major pita.
If you get an Edelbrock, spend the extra money on the AVS. Edelbrocks without adjustable secondaries seem to work on most engines but it is a useful feature. My non adjustable one did not work with my engine combination. As a result, the days of combined, unsuccessful tweaking to try to get a flat spot out on that carb were overcome in only a few hours with the Holley.
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By DryLakesRacer - 8 Years Ago
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Talkwrench. Thanks for your write up. A couple of things missing at least for me. How long did you have each carb on the engine and which one gave you the best fuel milage? It would seem to me the 460 Holley with its small venturi's would be the one. One other question; is the 460 Holley you used what Holley calls their 465 cfm for off road like rock crawlers?
One test I would like to see is one showing the many throttle body EFI's now on the market mounted on a B, Thunder, or Mummert manifold.
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By miker - 8 Years Ago
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Dry lakes, I don't want to hijack the thread, but I've got an EFI on a BlueThunder. Pm me if you want details.
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By DryLakesRacer - 8 Years Ago
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Thanks miker! Tried to send message but told your full and need to delete some. Instead if u like email me at gmc6power@ EarthLink.net and if you can include some photos. Thank.
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By paul2748 - 8 Years Ago
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I have an Edelbrock 600 (don't remember the number but manual choke) on my 312 powered 54 and it ran good straight out of the box. Had the same thing with another Edelbrock 600 on my mildly modified 302 in my 48 Ford (electric choke) which has been on the car about 15 years without an overhaul. I checked the plugs over the winter and they were great, nice tan color.
On the 48, I had a couple of Holley's (both new) and it seems that I couldn't keep either one in tune. That's when I went to an Edelbrock. Never had a hesitation or flat spot with the Edelbrocks.
I usually don't keep track of mileage.
The funny thing is that I have 56 Bird, 312 with a Holley 4000. This carb runs very good and I got 14MPG on a cross country trip (3.37's no overdrive 65 -70 MPH). The only Holley that hasn't given me trouble.
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By pegleg - 8 Years Ago
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I tend to agree with Vic. Also found the Edelbrock extremely easy to understand and tune using the Edelbrock tuning book and their kits. I run one on the Red F code and it has been bulletproof so far. 1405 600cfm.
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By Talkwrench - 8 Years Ago
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2721955 Meteor. I think I understand what you saying , but just cant see it working as you have to manually put it in first gear ? I ve never heard of this - anyone else? .. If you can find the article by all means put it up so we can see..
Dry Lakes.. The Holleys have been on for a few years each the Edelbrock is only just recent. Fuel economy; the Holleys were the same to me, don't ask me to quote mpg I'd have no idea. I think I would expect slightly better from the Edelbrock by going on the vacuum gauge, time will tell.
Yes, I would have thought the smaller Holley would have been best that's why I had it made up for me.. It is a 450 list 4548 - 0509. Not part of the off road - marine set, well as far as I know unless Phil changed the breathers etc .. I would have thought they might have centre hung bowls too..I don't know? I'd like to try one of the 500 Eddies, but of course I don't have one under my bench ; )
Charlie what has the Avenger series got that the old ones don't?
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By charliemccraney - 8 Years Ago
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Mostly, simply because it is a modern carb, it has modern fuel circuits. The other features, I think you can retrofit to older carbs, but older and old style do not come with them. Those are things like center hung float bowls, dual inlet, quick change secondary spring housing, secondary metering block. Some of them are available with 4 corner idle. For more info, check Holley's site.
Just for clarity, I'm talking about the lower end Holley carbs. I know there are older high end carbs that do come with many of the same features as the Street Avenger.
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By Ted - 8 Years Ago
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Talkwrench (4/9/2016)
..... What has the Avenger series got that the old ones don't?
To add to what Charlie has mentioned, the Holley Street Avenger series of carburetors are calibrated for more aggressive camshafts. Because many of the ‘larger’ camshafts have a reduced carburetor signal at idle, the emulsion holes and air bleeds are sized differently to obtain the correct fuel mixture in the lower rpm ranges. Many of the universal carbs have fixed emulsion and air bleed holes and are difficult to modify appropriately. The Street Avenger carbs while still having fixed sizes, are sized for more aggressive camshafts and work better out of the box with modified engines.
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By charliemccraney - 8 Years Ago
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According to Holley tech, the 570 is geared more toward stock engines. It is the 670 and bigger which are for modified engines and bigger cams.
What I have is the 570, which Holley would not have suggested for my combo, had I asked before buying, and my engine is not at all radical. I have acquired a 670 that I wil try soon. So, if your engine is stock or a basic rebuild, 570. If it is modified and you've gone up a couple steps or more on the cam from, say, the standard 1957 cam, 670 or bigger. And you can always call or email them and ask.
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By pegleg - 8 Years Ago
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Ted (4/9/2016)
Talkwrench (4/9/2016)
..... What has the Avenger series got that the old ones don't? To add to what Charlie has mentioned, the Holley Street Avenger series of carburetors are calibrated for more aggressive camshafts. Because many of the ‘larger’ camshafts have a reduced carburetor signal at idle, the emulsion holes and air bleeds are sized differently to obtain the correct fuel mixture in the lower rpm ranges. Many of the universal carbs have fixed emulsion and air bleed holes and are difficult to modify appropriately. The Street Avenger carbs while still having fixed sizes, are sized for more aggressive camshafts and work better out of the box with modified engines.What other differences are there between the 570 and the 670 Charlie mentioned, beside the obvious venturi sizes?
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By ian57tbird - 8 Years Ago
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Talkwrench (4/9/2016)
2721955 Meteor. I think I understand what you saying , but just cant see it working as you have to manually put it in first gear ? I ve never heard of this - anyone else? .. If you can find the article by all means put it up so we can see..
HI Rob.
My Tbird will go to first of the line if I floor it, since I adjusted the kickdown.
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By Talkwrench - 8 Years Ago
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How did you adjust it Ian , did you still line up the hole in the bell crank etc ? I have adjusted the threaded rod [the one direct to the trans] but that had no effect on making it go into first, it does hold the gear slightly longer however it seems to "load up" and clunk into first when nearly stoped.
I did find the linkage I made for the Edelbrock works better and if I floor it will kick to second. before I had to push it through the floor to have any chance.
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By ian57tbird - 8 Years Ago
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It was a long time ago, soon after I got the car but I think it was as the manual says. I remember that just lining up the hole was not enough but there should be some preload on the kickdown rod. I originally adjusted it because it was a bit sloppy, sounded like it was slipping under very light throttle, when almost coasting. I spoke to an old transmission guy who suggested I look at the kickdown first. That firmed up the shifts and the bonus of first gear when flouring it of the line.
Maybe catch up some day when this rain stops and I'll take you for a spin.
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By GREENBIRD56 - 8 Years Ago
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The Fordo transmission manual has some additional advice about setting up the kickdown rod (on my '56) - it involves reading a pressure on the control valve. Shows the proper port to attach your gauge to - but I don't have a reference to it on my computer these days............. I have heard / read that the use of the pressure as a set-point is the best way to get a consistent reaction. Hoosier would know.......
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By rgrove - 8 Years Ago
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At least on the 56 Fairlane, the rough adjustment for the trans is to get the kickdown rod to where it lines up with the hole on the bellcrank when pulled all the way up, and then lengthen the rod by 3 turns. This method has always worked well for me. The pressure gauge is the better way to do it, but I dont have one of those and havent sought out anyone who can do it that way.
I do believe that if it isnt adjusted properly it will lead to premature wear.
YMMV
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By GREENBIRD56 - 8 Years Ago
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The thing I learned - the hard way as always - is that once you have the rod in the alignment holes - you then must set-up the height of the gas peddle off the floor. Spec was in the Fordo manual. This is so that there is sufficient travel available for the kick-down rod to travel the proper amount to work it's lever in turn. Make sense? When the peddle is too near the floor - mashing it won't result in enough kickdown movement to get the proper shift pressure. Just turn in in the screw on the kickdown raises the pressure OK - but then, back at part throttle the shift may still be harsh.
I've run my outfit with a Holley 600 cfm - and now a Demon 525 - and the internal throttle springs (of the carb) are so different than the linkage was initially designed for - much tinkering is required to balance the spring forces.
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By Talkwrench - 8 Years Ago
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Seems like I have to go and check my linkages all over again .. I remember going through all of this years ago but I'd say it must be out of whack with all the carb changes ... Now to find all the info on lining it all up again .. More-so to get it right so I have first gear if I floor it ...
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By GREENBIRD56 - 8 Years Ago
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This is the diagram I came up with for the T-bird years ago - shows a few of the little gadgets Ford put in there.................. To get mine to work, I had to put an adjustable stop on the back of the manifold to get a consistent pedal stop height. The diagram just shows the carb and throttle - not the kickdown rod.
As the pedal is depressed, the carb throttle blade rotates until it stops turning (wide open primary) - there is remaining space between the pedal and floor. As the pedal continues downward, the mechanism is rotating, moving in the kickdown slot - continuing to move the kickdown rod still further downward.
The carb can be at full wide open - but the kickdown must travel further to get full actuation pressure - and downshift the transmission.
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By Talkwrench - 8 Years Ago
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Im sure Ive got your diagram lying around Steve from last time.. And I understand what your saying about the need for having that little bit extra on the pedal for it to work. I did mean to have a look last night but unfortunately received further bad news about my father inlaw, he now has another brain tumour.. Great!
I did find something on throttle linkage adjustment yesterday seems passenger cars have 3 1/2" to the floor matt and Tbirds have 4 1/2" ..?
I did also read that you can put the trans in "low" when driving along over 20 mph [but I bet not at 60!] and it will change to second 'intermediate' gear ... seems there is more to the "fordo" than meets the eye.. I always thought that the first gear [low] was like a manual lock out.
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By ian57tbird - 8 Years Ago
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From what I recall, get pedal travel wright first then set the kickdown.
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By GREENBIRD56 - 8 Years Ago
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As I recall - racers (with stock outfits) always would leave in LOW with the Fordo - use the lever to initiate up-shift, then swiftly return to LOW to hold the second gear.
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By Talkwrench - 8 Years Ago
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Well I seem to have it working ok but now I remember why it never worked that well the bell crank is flogged out.. I've spent a bit of time on it and made an adjustable throttle rod. I have to hit the floor pretty hard but it will kick down and I can now take off in first. Sometimes it goes real well and other times it short shifts. I've adjusted the trans link and it shifts at about 28 mph on a moderate take off. I've even try putting it in low above 20 mph and it works it shifts into second, the only thing is if you go too slow (10-15) it will drop into first.
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By pegleg - 8 Years Ago
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Steve, we did, and it worked.
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