RE: {Chrysler 300} 64 K accelerator pump question

Allen, the accelerator pump exits through the jets. The diameter of the jets sets the rate of flow of the jet. A larger well would mean a longer squirt, not a larger squirt.

I think I have is write in my head, but these days who knows…

I will go look when I am back up in Winters as I have a spare carb up there.

An interesting dilemma.

James

From: 'ALLAN POZDOL' via Chrysler 300 Club International <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Sent: Sunday, July 19, 2026 13:37
To: chrysler-300-club-international@xxxxxxxxxxxxxxxx
Subject: {Chrysler 300} 64 K accelerator pump question

I have been going in circles on a replacement accelerator pump configuration. My carb was rebuilt with a 3/4" but shorter pump. Aluminum has worn into the leather after a short time, so i thought I had to replace with a 11/16".

The manual and the Carter product pages state that the 3614S takes an 11/16" pump. The well measures 47/64". As does a 3615S for an Imperial and New Yorker.

I now find this little snippet online:

Why Your 3614S Measures 3/4" (Instead of 11/16")

Carter's official technical charts for the 3614S blueprints list an 11/16" pump cup, but you are holding a 3/4" bore in your hands for one of two highly common reasons: [1, 2]

Mid-Year Production or Heavy-Duty Casting Changes: Carter frequently updated castings mid-run or shared cast bodies across different assembly lines. Heavy-duty applications (like the high-performance Chrysler 383/413/426 Wedge big blocks that the 3614S belonged to) were routinely upgraded to the larger 3/4" accelerator well to dump more fuel and eliminate the off-the-line flat spot inherent to moving massive Mopar B/RB-body cars.
A Past Machining Rebuild (Sleeving/Boring): It was incredibly common for commercial rebuilders in the 1970s and 1980s to clean up pitted, corroded aluminum Carter wells by boring them out exactly 1/16" oversized to accept the larger 3/4" plunger cup.

Has anyone else run into this issue? Both bores and scored up a bit, so I don't think they were machined any larger in the past.

Allan

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