Edelbrock carb question

[Whisler]

I am posting this here because I know that "someone" here is an Edelbrock enthusiast.

So I purchased a used Edelbrock carb. off CL in very nice condition for $100. I thought it was an 1406 (650 CFM, electric choke). As I am moving closer to installing it I looked it over today and noted that the number stamped into the front base is not 1406 but 1806. So it appears I purchased an AVS Thunder carb.

Are there many differences between the Performer and the AVS carb? I have read that the secondaries are more easily adjusted but that is all I know. Please enlighten me.

Thanks in advance.

[Gary Lewis]

Woo hoo!  The Air Valve Secondary was the next step in evolution from the Aluminum Four Barrel AFB.  The big difference is that the secondary opening time is easily adjusted where the AFB requires a complete disassembly of the carb and either grinding weight off or adding weight to the bobber.  But on the AVS you just hold a screw, loosen the clamp slightly, turn the adjusting screw, and clamp back down.  Takes less time than pulling the air cleaner.

I really like the AFB, but would much rather have an AVS.  I'm sure there are other improvements, and Bill could surely tell us, but that's the one I appreciate the most.

[Whisler]

Thanks Gary. I was hoping you would reply. I was sure hoping I hadn't thoroughly messed up with this purchase. Sounds like I didn't do too bad. Do you know of any problems mounting this on my 351W, that are different from the Performer. I already bought adapter pieces, thinking it was a 1406.

Any further enlightenment gladly accepted and appreciated.

[Gary Lewis]

I've not run an AVS on a 351W, but recently set up one for Brandon/Bruno2 for his 351W.  However, he doesn't have his engine in the truck yet, so we don't know how it runs.

As for tips, the AVS is so similar to the AFB that there shouldn't be enough difference to worry about.  And I think we covered many of the common issues in this thread.  That would include fuel pressure, throttle cable bracket, and choke.

[reamer]

7 psi, 7 psi , 7 psi .......

[Whisler]

An add-on question, if I may. Now that I know how easy it is to regulate the secondaries, how about a few tips on deciding when they should open. My experience with carbs has been all 1 and 2 bbls., except for my 1956 Studebaker Golden Hawk and it never needed any work on the 4 bbl.

[Gary Lewis]

First, Ron's comment about 7 psi is spot-on.  Eddies don't like more than 6 psi, so a regulator is sometimes necessary to ensure you don't overpower them.  What will happen is that at idle the pressure on the needle will cause the float level to raise enough to make the idle mix rich.  Or even cause the carb to flood.

I've not had it happen, but then I've run a regulator on my Fords.  Back in my Chevy days the fuel pumps didn't put out too much pressure, but the Ford pumps can.

As for the secondary air valve adjustment, you want it to open at the earliest possible time that the engine can use the extra CFM.  So you experiment.  Do a full-throttle run from a rolling start in 1st and see if the secondaries open w/o bogging the engine.  Then loosen the tension on the air valve's spring by maybe 1/4 turn and go again.  Keep doing that until at some point the secondaries open too early and the engine bogs, meaning that its acceleration hesitates.  At that point you have gone too far, so tighten it back down 1/8 turn and try again.  You want to find a spot where it never bogs but opens as early as possible.

[Whisler]

Gary, thanks for the excellent explanation on setting the opening point of the secondaries.

Also I will most definitely look into the fuel pressure regulator that you linked and Reamer seconded. :)

[grumpin]

Whisler wrote

An add-on question, if I may. Now that I know how easy it is to regulate the secondaries, how about a few tips on deciding when they should open. My experience with carbs has been all 1 and 2 bbls., except for my 1956 Studebaker Golden Hawk and it never needed any work on the 4 bbl.

Dang...nice!

Got to ride with my Dad in a Silver Hawk!

[Whisler]

I had 4 Studebakers over my young years, a 1950 (bullet nose), a 1953 (sleek design), a 1956 Golden Hawk, (Packard/Hawk), and a 1957 Silver Hawk. My 2 favorites were the 1953 for its beautiful body design and the 1956 for its combination of looks and power.

The '56 GH was the first year for the GH and the year that Studebaker merged with Packard. They basically took the 1955 Power Hawk body, added small upright fins and replaced the Studebaker V-8 with the larger Packard V-8. In '57, the GH went back to the Studebaker V-8 and added a supercharger and larger,swooping fins.

The '56 GH was a blast to drive; it was geared in such a way that it turned 1000 RPM/30MPH in high gear.
On the open road (interstate) the only car that I ever had out accelerate me from 60 MPH up, and I ran against some big, powerful cars, was what I believe to be a dual quad Corvette.
I'm pretty sure it had dual quads, because when we both nailed it at 60 MPH I took off like a shot and he nose-dived and bogged. When he got it wound up he went by me.

It's a wonder I survived my youthful driving! Don't tell my kids!

[grumpin]

That's great! Those were cars!