Hello all

Wondering if anyone here with dual 4 bbl experience (Teapot carbs) knows if the secondary springs are/were lighter than those used on a regular 4 bbl appplication?

Thanks

Jim

I have always had to use the lightest spring that is in the Holley secondary spring kit to get them to open easily when using regular 56 ford teapots on a 2-4 intake.  You may have to buy two spring kits, just to get two of the light springs you want. 

I added an edelbrook A/F ratio meter that really helped me get the jets dialed in properly.

The E-code carbs have a different venturi, so you can't just use the same jets as they do.

I had to solder up and redrill the secondary jets to make them smaller on a regular '56 ford teapot, as well.

Adding the secondary tube to connect the two carbs like on an original e-carb, is easy to add, and helps the secondaries open at the same time, yet make it look more correct as well.

My last set-up ran really well and got up to 18mpg on trips.

Pat Fleischman

The secondary springs in the dual quad carbs have essentially half the tension of those in the single quad applications.  This is due to the vacuum signal being reduced in half to each carb when using two of them as a pair.  The long yellow spring in the Holley spring kits would be the stock spring for the dual quad applications.  As Pat mentions, it will take two spring kits so you can keep matching springs in both carbs and using even lighter springs will have the secondaries opening earlier.  The short yellow spring would be the next quicker opening spring while the white spring would be the lightest.

Lorena, Texas (South of Waco)

Hi Pat & Ted

Thanks for the information. I was wondering if the Holley spring kits sold would work. Thansk again

Jim

Also, Pat, I'd love more info on the secondary jet downsizing and what size dril you ended up using? I did add a balance tube for the secondary vacuum.

Thanks

Jim

I had to solder the longer secondary jet up and redrill them, as they are too large for a dual quad application.   I think I used the stock figures, 55 for a dual quad car when I redrilled them, as the secondary air and fuel track on seems to be the same on a e-code carb and a '56 ford carb.

I still recommend getting an Edelbrock fuel ratio meter, PN EDL-6593 $139.95, from Summit, so you can figure out wha tis really happening when you make changes.   I have mine on a plug in harness and mounted in velcro, so I can remove when I don't need it.   All it takes is the included O2 sensor mounted in one of the exhaust pipes.

Pat Fleischman

When I first put my dual quad setup together in '65 I used the '56 single carbs and jetted them according to a '62 Hot Rod Magazine book on Ford engines. Had a heck of a time finding the correct jets for the secondary's but finaly did. Ran great. When I finaly found the prober carbs, found that the jetting was way too rich. Jets same as for '56 single carb. Subsequently found second set of correct carbs. They also had single carb jets. I have wondered ever since if many of the problems with the original dual quad setups back in the day was not because Holley somehow put the wrong jetting in many of the carbs causing them to run way too richj. Ford parts books show jet sizes close to the Hot Rod recomendations. Any one else out there with original carbs ever checked the jet sizes?

Slumlord:

My '56 dual carbs (EDB-C) came with 45 primary, 55 secondary, and 38 power valve jets.

John - "The Hoosier Hurricane"

OK guys. I really appreciate the info here and think it'll really help down the road.

Pat- I did put in bungs for an AFR gauge when I built the headers. That Summit item looks like something I will get. Thanks

Slum- I'll do some research and see about that 62 HR article

Jon- Those jet sizes that you provided, Thanks 

Regards, Jim

Jim:

Those primary jets will be too lean in a regular '56 carb.  The secondaries should be close.

John - "The Hoosier Hurricane"