throttle plate issue

[sacramento_ford]

i had a autolite 2100 for a 390, i meesed up i think and got one from a smaller engine, sinves its rebuilt already, will using the smaller throttle plates work ok in a 390, or should i just go back to larger plate, thanku

[willowbilly3]

What venturi is it. Look for a number in a circle on the side. Here is the cfm but remember they are rated different than 4 bbl. I think the 1.21, 1.23 would be for 390, the 1.33 may have been the legendary 429 2 bbl. Even the 350 won't take you much past 4 grand on a 390. I ran 1.23 and then a 350 holley and they both worked great for a tired old truck but faded fast if you wanted to rev out a little.

From a sticky at Fordsix


0.98 = 190 CFM 24.9mm/24.9mm syncronous venturies.
1.01 = 240 CFM 25.6mm/25.6mm " "
1.02 = 245 CFM 25.9mm/25.9mm " "
1.08 = 287 CFM 27.4mm/27.4mm " "
1.14 = 300 CFM 29.0mm/29.0mm " "
1.21 = 351 CFM 30.7mm/30.7mm " "
1.23 = 356 CFM 31.2mm/31.2mm " "
1.33 = 424 CFM 33.8mm/33.8mm " "

When comparing to 'metric' carburetors, remember that venturi size is not the same as bore size. In example, a Weber 32/26 has venturies of 26mm/27mm.

Link to original thread:
http://fordsix.com/forum/viewtopic.php?p=301509




Remember that four barrels are flowed at 1.5 "hg. So these flow numbers do not equate to 4V flow. To convert divide by 1.41.

So, for example, a 190 2V would be equivalent to a 135 4V.
A tri-power using 3 of these 190s equals a 404 cfm four barrel.

[fordman]

it will run if you use the whole cabr as one unit. but i don't think you can swap that plate and make it work properly.

[Alvin in AZ]

Since the throttle plate size is the same between a 1.23 and a 1.33...
I've thought about reaming the venturi out of a 1.23 to ~1+1/3" as an experiment. :)
Anybody done that?
I'm sure a guy could get it to work with enough fiddling around. ;)

Alvin in AZ

[fordman]

Since the throttle plate size is the same between a 1.23 and a 1.33...
I've thought about reaming the venturi out of a 1.23 to ~1+1/3" as an experiment.
Anybody done that?
I'm sure a guy could get it to work with enough fiddling around.

Alvin in AZ

if you were experienced enough maybe you could do that. but for the guy who is having carb problems do not try this because it won't fix your carb.

[Alvin in AZ]

...for the guy who is having carb problems do not try this because it won't fix your carb.

LOL! :)

Yeah, SactoFord... what size did you end up with?
...and tell us some more symptoms! :)

Alvin in AZ
ps- when I lived in there I called it "Suck-my-toe"