Late response to this
subject. I have been in overload building my new shop. Ready for roof and
stucco. Being 75' long with 16' 4/1/2" plate height, my neighbor asked when the
Costco was going to open.
I may be able to shed some
light on pump subject. I am restoring a 57C. I made it my business to learn more
about the two different pumps. I acquired several of each pump including
NOS.
The 2610
does NOT have a notch on the flange. The reason for different p/n is
the later has a press-in intake nipple, the 2503 had a thread-in nipple.
Hence the different p/n. Both 2503 & 2610 use the same rebuild kit so, both
have the same diaphragm size, I think 3" and would not require a notch. I also
have a couple of after market pumps. Some had a 3 1/2" diaphragm and required a
notch to clear the corner of the block, and the notch does look like it is
hand cut after the pump was assembled.
Carter pumps "always" have
CARTER cast on the side on the body. You can't miss it. Any pump without
CARTER cast on it, or has a notch, is after market. Further, Carter pumps
have the part no's stamped on the flange where pump attaches to timing cover.
Also, 57 C's never used a pump with filter cast on the bottom. 58D's had a
Carter pump with a ceramic filter w/ glass bowl cast on the bottom,
p/n M2663S. In an effort to cut cost, Chrysler put the filter on the pump and
eliminated two filters at the carbs. Both 57 pumps will work on a 58.
There was a question about
what motors used the 2503 & 2610 pumps. All models used the same pumps, 2
brl, 4 brl, & 2 x4 brls. I purchased two 57, 2 brl poly motors.
Both had Carter 2503's.
I have a NOS M2503S for
sale. It was tested by my expert pump rebuilder. He told me the Carter pump
had a patented lever design for high volume. The after market pumps had to
use a larger diaphragm to accomplish the same volume.
I have photos of all the
pumps. As time allows I can forward.
Thank you,
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