It's time to get a new carburetor for my y-Block.
I have a mildly upgraded 272 Y Block in my '54 F100. It has been balanced and rebuilt by Ted Eaton using big valve heads and a mild cam upgrade. I am using the FORD ECZ-9425-B intake manifold. It is used for cruising and towing a boat, so I don't want a fire breathing dragon, and fuel economy is nice. The current 600 cfm Carter AFB Quadrajet has seen better days and is leaking at the throttle shafts.

I am considering trying one of the Demon Fuel Systems "Street Demon 625 cfm" #1900 4 bbls. Does anyone have any experience with this carb on a Y-block?? Does it have the large vacuum port for the Y-Block PCV system hose?
Any other carbs I should be considering that offer simplicity with a combination of performance and economy?
Thanks and regards, Jeff

 

I have a mild build 292 and when I talked to Holley they said 600cfm is too much...I am looking at 390 or 450 cfm Holley carbs. Did you have any rich condition issues with your 600cfm Q-jet?? Thanks -

 

Just because you have a 600 cfm carburetor on your 272 it does not mean your engine could flow 600 cfm. With that big of a carb I doubt your secondaries are even opening. I would suggest a 390 or 450 cfm.

 

Almost hi-jacked thread...sorry. My 292 is .060 over, mild cam, larger valve heads, and dual exhaust (manifolds) and I am over carbed with the 600...just FYI...

 

Yes, to address all your comments, I seem to run on the rich side, and have experienced some hesitation when at speed and step on it. It feels like it is starving, yet there is all that carb up there!!
I suspected there is a problem with the secondary's, but I didn't think that they could not be opening. How could that be - not enough vacuum to open them?

 

Also, one carburetor I was considering was the Edelbrock 1403 which is 500 cfm. It would be a drop in replacement for my Carter AFB in terms of throttle linkage and choke.
Still too much for my 272??
Jeff

 

Yes, though it will work. The 390-460 cfm mentioned above would be better.
Big valves or small, the displacement is small.

 

Jeff, The Edelbrock is a good carb. That's what I'm running on my 318" Y-Block. Like most modern carbs it has the port for your PCV valve and both ported and manifold vacuum connections.

 

Hey Y-Blockhead,
Which version are you running on the 318 - 500 cfm? I took a quick look on Summit's website and 500 cfm seems to be the smallest.
Jeff

 

Jeff, yes it's the 500cfm, #1403 with electric choke. Be aware that the bores in the secondaries are slightly larger than the "B" manifold and you will need to use a spacer to keep the butterflies from hanging up. I use a phenolic spacer to isolate the carb from heat (you don't need one as thick as mine).

 

Dennis, I took a look at carb spacers, and man there are more choices than carburetors! With the 1403 and the B manifold, do I want the "4 hole" style or one of the other more open designs?
Thanks, Jeff

 

Since your using your truck for towing, go with a four holer. The open plenum design is more for upper RPM power. I believe the original one on a "B" manifold was ~ ½" thick.

 

Yes, I think my current unit is an original - 1/2" brown phenolic. Well used!
Thanks, Jeff