403 Carburetor Jet and Metering Needle Size

[Greg C.]

My original carb had the fuel filter housing JB Welded in. In order to get the coach running, I bought a used carb from Chuck Boyd from a 1978 coach.
Supposedly, the 1977 and 1978 carbs are identical. They even have the same number except for the year designator. And this one was labeled
REMANUFACTURED.

When I pulled the top off the new carb, it was obviously going to need gaskets, pump, etc, so I ordered a good kit and bought Cliff Ruggle's Quadrajet
book. I used to build Quadrajets back in the day, but this book is very helpful.

Anyway, what I read in Cliff's book took a little air out of my sails in that he states remanufactured carbs were built with a generic jet and needle
combination so they would run several different vehicles with some level of success, but they are not tuned vehicle specific. That means it most
likely does not have the TZE factory original jets and needles. I'm not so much concerned with the secondaries, but I would like to get the correct
jet/needle combination for it on the primaries.

I'm also going to have to put bushings in the base plate, as the throttle shaft bores are worn, a typical problem for these.

So, does anyone know what the factory jet/needle combination was for the 1977/78 403 for our coaches?

Thank you.

--
Greg Crawford
Knoxville, TN

1977 Royale
403
Rear Bath
American Eagle Wheels
Alex Sirum Quad bags

 

[jim kanomata1]

Greg,
Just call Dick patterson as he has all that info.
If you needn his contact, call me.

On Tue, Sep 8, 2020 at 7:37 AM Greg Crawford via Gmclist <

> My original carb had the fuel filter housing JB Welded in. In order to get
> the coach running, I bought a used carb from Chuck Boyd from a 1978 coach.
> Supposedly, the 1977 and 1978 carbs are identical. They even have the same
> number except for the year designator. And this one was labeled
> REMANUFACTURED.
>
> When I pulled the top off the new carb, it was obviously going to need
> gaskets, pump, etc, so I ordered a good kit and bought Cliff Ruggle's
> Quadrajet
> book. I used to build Quadrajets back in the day, but this book is very
> helpful.
>
> Anyway, what I read in Cliff's book took a little air out of my sails in
> that he states remanufactured carbs were built with a generic jet and needle
> combination so they would run several different vehicles with some level
> of success, but they are not tuned vehicle specific. That means it most
> likely does not have the TZE factory original jets and needles. I'm not so
> much concerned with the secondaries, but I would like to get the correct
> jet/needle combination for it on the primaries.
>
> I'm also going to have to put bushings in the base plate, as the throttle
> shaft bores are worn, a typical problem for these.
>
> So, does anyone know what the factory jet/needle combination was for the
> 1977/78 403 for our coaches?
>
> Thank you.
>
>
> --
> Greg Crawford
> Knoxville, TN
>
> 1977 Royale
> 403
> Rear Bath
> American Eagle Wheels
> Alex Sirum Quad bags
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[Greg C.]

Jim, thank you. Dick emailed me the information directly. Thank you Dick!

Oh, and FYI, he said the main jet is: 1977 403 main 75, rod 54M Calif. main 78, rod 54M
1978 403 main 74, rod 54M Calif. main 78, rod 54M
--
Greg Crawford
Knoxville, TN

1977 Royale
403
Rear Bath
American Eagle Wheels
Alex Sirum Quad bags

 

[john r. lebetski]

Well that seems very odd that Caif emissions would use several sizes richer jets than Federal. Maybe to limit NOX? At the expense of higher HC
emissions? Anyone know?
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[emerystora]

John
I gave up on trying to figure out why California does things years ago. I lived in Tiburon years ago from 1984 to 1993 but am glad I moved out. Great place to live but hard to take the politics, taxes and extreme liberalism.

About 50,000 Californians moved here last year so we are starting to remind me about all the bad things about California.

Emery Stora
77 Kingsley
Frederick CO

>
> Well that seems very odd that Caif emissions would use several sizes richer jets than Federal. Maybe to limit NOX? At the expense of higher HC
> emissions? Anyone know?
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[johnny]

For us Alabama boys living in Georgia, moving from California to Colorado is simply jumping out of the fire and back into the frying pan

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell