Bewy said

If you want to increase the 1-2 upshift speed, you can do it without removing the pan.
If you have a carb with large throttle bores, it requires less throttle opening than a carb with small t/bores....to get to the same road speed [ shift speed ]. The K/D lever moves less with a big carb, all else being equal; & the trans shifts earlier, all else being equal.
The above demonstrates that it is a 'ratio thing '.

If you want later shifting: there is a rod from the carb that goes to a bracket/linkage at the back of the engine. Where this rod hooks onto the bracket, the hole or stud on that bracket needs to be repositioned closer to the pivot.
The idea is: for the same throttle open position, the K/D lever moves further, increasing line pressure & delaying the shift point. You might need to experiment with different hole positions. The same thing can be achieved with the K/D lever on the trans; move the linkake hole closer to the

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JDMopar said

When you have it adjusted properly, under normal driving conditions, it should shift from 1-2 at 18 mph and from 2-3 at 28 mph. If it is short shifting (too early) make the rod longer by unscrewing the adjustment at the carb. If it is holding too long and shifting late, shorten that same adjustment a few turns at a time to get it dialed in. Obviously, the more you mash the gas pedal, the more throttle pressure the valve body sees and will hold shifts longer, as it is designed to do. You do not want to lengthen the throttle pressure linkage to the point that it keeps the carb butterflies from achieving wide open throttle, like @RustyRatRod advised above. It is also important to have a small spring pulling the throttle pressure linkage forward towards the carb stud that pushes it backwards. If there is a gap between the stud on the carb and the linkage slot, the valve body isn't seeing any pressure applied from idle to wherever the stud finally catches the slot and starts pushing. Go back up to post #2 and look at the pic. See that little triangle shaped tab welded to the kickdown rod? The little spring goes in the hole in that tab and hooks to the end of the carb stud to hold the adjuster to the rod at all times. Keep plugging at it, and you'll get it figured out.

:thumbsup:

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