1964 Thunderbird carburetor advise

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Hello all! I’m new here so let me introduce myself, I’m Chuck in south central PA and I own a 1964 convertible. Doing some research on a replacement carburetor and noticed that several 4th generation T-Bird owners have gone with the Holley 670 Street Avenger. Have a few questions on items that I couldn’t find (or just plain missed :) ):

- Did you need to make any changes to the throttle linkage or kick-down?
- Were you able to use the stock air cleaner?
- How did you wire the electric choke?
- Are you satisfied with the carburetor swap?

Thanks in advance for any and all feedback.

Chuck
 
I need to replace the carb on my father-in-laws '64 T-bird. Should I stay stock or go to a Holley 600? If I choose the latter, does the T-bird require the vacuum secondaries or mechanical? I'm pretty sure it uses an electrical choke. Please advise. I can't get to the car for a few weeks...
I tried to overhaul my Autolite 4100. But When I put it back on my 64 Thunderbird it just seemed tired. I went with the 670 Holly Adventure and my Thunderbird runs fantastic. Now I did run a power line from the key/power side of the fusebox to the electric choke. Very simple to do and then less problems when cold starting.
 
Hello all! I’m new here so let me introduce myself, I’m Chuck in south central PA and I own a 1964 convertible. Doing some research on a replacement carburetor and noticed that several 4th generation T-Bird owners have gone with the Holley 670 Street Avenger.
I don't have any firsthand experience, but I definitely read repeatedly that the 670 CFM is the optimal size with many buying the Holley 670 Street Avenger and the Holley Street Demon 625 is more of a "plug & play" equivalent to the factory Autolite. https://www.amazon.com/gp/product/B008EL4DC8/?tag=thunderbirdforum-20
 
Hello all! I’m new here so let me introduce myself, I’m Chuck in south central PA and I own a 1964 convertible. Doing some research on a replacement carburetor and noticed that several 4th generation T-Bird owners have gone with the Holley 670 Street Avenger. Have a few questions on items that I couldn’t find (or just plain missed :) ):

- Did you need to make any changes to the throttle linkage or kick-down?
- Were you able to use the stock air cleaner?
- How did you wire the electric choke?
- Are you satisfied with the carburetor swap?

Thanks in advance for any and all feedback.

Chuck
Hi there. I just installed a 670 street avenger on my '64. Looking at your questions and here's my input:

- For the throttle linkage, you have several options where to connect it to the carb linkage. Just make sure that when the gas pedal is pressed all the way to the floor, the throttle is WOT, otherwise you'll be giving up some potential power. What I did before connecting the throttle linkage was to open the carb wide open and make a register mark on the side of the carb. Then connect the throttle linkage where you think it should go and see if you get WOT. I'm away from home but will send a photo of where mine is connected when I get home early next week.
- I wouldn't use the stock air cleaner housing. It's cleverly designed to restrict the flow of air into the throat of the carb. Get a circular filter housing and use a K&N or equivalent free flow filter. More air = more power.
- The choke "+" wire has to connect to a source of a full 12 volts when the ignition is on. In my case, that was the "+" terminal of the coil, but that's because I installed a Pertronix relay to supply a full 12 volts to the coil when the car is running. With the old style resistor wiring, the coil is getting less than 12 volts when the engine is running.
- I was replacing an older 670 street avenger carb that was getting kind of cranky. The new one works like a champ, smoother idling, better throttle response and more power.

Doug
 
Thanks to everyone for the feedback. Will definitely look into the Street Demon. It’s been a challenge getting the car to run properly with the 4100.

Doug, sounds like you really like the performance aspects of the 670. I have more years, and probably more miles, than my T-bird so I’m going more for driveability (though more power is always a good thing :) ).
 
Hi there Daniel. Yes, I have a 670 cfm street avenger with vacuum secondaries on my '64. I bought it direct from Holley a few months back. Definitely a great carb and the size is well suited to the 390. Doug
 
I'll pitch in here and mention another one, in the same family. The Street Demon 625 is also an excellent fit for a stock 390.

I love the composite fuel bowl on the big FE in a TBird. As you may know, the Bird has a different engine mounting scheme then the rest of the 390/428's of the era. It's mounted level; the Galaxies etc had it mounted with a fore-and-aft lean. Ford put a wedge in the manifold design to correct it and th 'Bird got a heavy phenolic plate under the carb to correct the heat issue. I find a composite bowl goes a long way in helping the problem, especially if you need to replace the really heavy cast-iron Ford intake (75 lbs) and run into hood-clearance issues requiring replacing that wedge. Modern square-bore insulators are available that are thinner but the composite bowl is a terrific feature. "Keep the fuel . . . . cool"
I would also add that in practice the Demon is a huge performance upgrade to the 4100, which depending on the 1.08 venturi & 1.12 venturi really flowed somewhere between 480 - 580 (NOT the 600 normally published) CFM. I remember a great article by Bob McDonald in "Engine Builder" a few years back that showed that even in a heavily modified 390 his best performance was at 650 CFM on a carb (EFI actually was less reliable) and was making in between 500 to 600 HP with over 500 ft/lb of pull.
 
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Hi there Daniel. Yes, I have a 670 cfm street avenger with vacuum secondaries on my '64. I bought it direct from Holley a few months back. Definitely a great carb and the size is well suited to the 390. Doug
Holley says their carbs should not require adjustment out of the box, but I had to tweak the accelerator pump linkage and crank down the adjustment on the fast idle screw. Other than that the carb has been flawless and a huge improvement over the used street avenger carb I was running before.

I've not had problems with fuel overheating. But the way things are going with heat waves here in the western US, this is a potential issue to be aware of.
 
I've seen a few cars actually boiling gas in their fuel bowls. I'll bet if you search this forum you'll find a couple. It was a common problem on these engines with that heavy cast iron manifold. It's why these cars were shipped with that heavy plastic spacer mounted on the carb pad with the coolant fittings. Here's the original Ford part:
(biddle - for informational purposes - NOT trying to sell anything!)
If you look at this seller's 3rd picture you can see the wedge shape I spoke of earlier. TBirds need that because their engines are mounted flat but their manifolds were wedge shaped to accomidate the other FE equipped cars Ford cars like the Galaxie who had them mounted on a slant. Anyone making any real changes on top needs to take this into account.
 
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