Rebuild of Caddy 7045230 carb

[Corto]

Hi,
as you know this is a carb with recomendation to be avoided...
But I have it in my recently aquired '75 Eldorado, and since I am going to have this car as an oldtimer, I would also like to keep the original carb.

I have read the Cliff's book - great book, thanks Cliff - and have some questions regarding rebuild.

I am going to keep this carb, but still thinking either to keep the auxilary rod/jet or to block them and use only the primary.
I am primarly interested in mpg (not suprisingly, I am from Europe), and since it will be an oltimer, the performance is of secondary importance.
I will also do some tuning of the timing, but I am starting with the carb.

Now, I haven't seen any special receipt for mpg efficiency so I assume that for the mpg it would be enough to properly rebuild the carb, but no other changes?

Regarding auxilary metering, it seems as a good idea to divide the primary into two substages. I can imagine that for the performance builds it might be complicated and not necessary, but for a street I would expect that it improves efficiency?
But it is interesting that the same year California curb didn't have auxilary jet/rod (only main primary)!?

In the rebuild kit for the 7045230 do you supply also the auxilary parts?
Do you have different springs for the auxilary and main primary pistons, to more precisely tune their kick in points? Do you have any recomendations?
For my application (street/oldtimer), do you think I can keep original rods/jets, or some other combination would be better?
In one doc I have found the codes of the rods/jets, but have no real dimensions.

Or would you recomend to block the auxilary jet (and vacuum port) and to go with the main primary only?
In this case I assume I would need another primary jet/rod?

Thanks,
Corto

[Cliff Ruggles]

If you are building it for a stone stock application, it can be left completely original.

We also have the parts if you decide to eliminate the auxilary power piston and single jet/rod.  I prefer this course of action instead, then you can use the front located APT system to fine tune if/as needed.

For those units, we use a slightly smaller jet with a larger primary rod, than would typically be needed, then add fuel under the jets with the APT system located in the front corner of the carburetor. 

I've built scores of them with perfect success, they are just a bit more labor intensive than the later APT style carburetors, but the end result is pretty much the same.

You would need an HP rebuild kit, and add primary jets and metering rods to it.  Just plug the hole for the front power piston, block the jet hole in the bottom of the casting, install the new parts, completely/correctly rebuild the carburetor, and tune it on the the engine once it's in service......Cliff

[Corto]

Thanks Cliff,
what is the best way to block the auxilary jet and power piston hole?

Currently I am trying to find one more carb, so the original one would stay as it is, and the other one would be reworked to be without auxilary.

Thanks,
Corto

[Cliff Ruggles]

Melt a tiny amount of lead or solder into the jet hole, and swag it in place with a punch.  Melting some lead into the PP hole works fine there as well....Cliff