Frank, I'm not a member of the Slant 6 group, however I receive technical inquiries from members quite often. I'll address your question, however with an e-mail address I could forward a picture of the Torqueflite upper valve body casting showing the necessary factory feed-port location to actuate the part-throttle downshift accessory.

Installing either of the 2 OEM part-throttle accessories onto the 1960-66 Torqueflite valve bodies can be done in 2 ways. Easiest method is to obtain a 1967 (preferable) or 1968 upper valve body casting and simply mate it to the 1960-65 or 1966 lower casting & separator plate. The 1967 casting allows installation of the front pump check valve; the 1968 casting does not. My experience has been that the Torqueflite will operate properly and dependably without the front pump check valve in this case.

To install the part-throttle accessory onto an original 1960-66 upper valve body casting it is easiest to use the 1971+ part-throttle version. The first step is to locate the necessary internal passage in order to access it to obtain the actuating pressure for the part-throttle installation. Once located the internal passage can be accessed externally by "step-drilling" part way into the passage with a 3/16" drill bit modified to a blunt tip and re-sharpened.

The 1971+ part-throttle valve body accessory will also need to be "step-drilled" on the topside to accept a 3/16" tube configured to join it with the new port in the upper casting. Once both new holes are drilled it is a simple matter to fabricate the 3/16" tubing to connect the 2 new ports.

I generally also fabricate a piece of light sheet metal to serve as a clamp to secure the tubing from dislodging from either port. A sealer can be applied to each end of the tubing, however if the fit is tight between tubing and the 2 new holes the P/T should work even with a slight bit of leakage.

Attached photo [below] points out the location of the 1967+ OEM feed-port for the part-throttle kickdown accessory. The area behind the upper, rear point of the upper arrow is where a hole would be step-drilled from above into the upper casting to obtain the correct fluid passage on a 1960-66 valve body to actuate the part-throttle accessory. I can get a photo of the location if you’d like.

Offering and dispensing technical information accumulated over the last 40+ years has become a larger part of my time. My local Torqueflite business takes up quite a bit of the day as does the eBay Store and answering tech questions for hobbyists. To that end I’ve not been active with any of the hobbyist groups as the 24-hour day only allows a finite amount of time for a myriad of activities.

People are welcome to contact me if I can be of help or assistance. You are welcome to pass along any info I provide as sharing information is a service I believe is important to all interested parties.

Thanks; let me know if I can be of further assistance with parts or information.

Pat

seems Chrysler was out to get 0.1 MPG better fuel economy regardless of drivablity complants.

I’m in the final process of preparing the P/T kits and installation information to add the part-throttle kickdown accessory to the 1960-66 valve bodies. Attached pictures [below] show the location of the hole drilled into the upper casting to access an external source of fluid to actuate the P/T. Kits should be ready for market in a week or so.

Thanks; let me know if I can be of further assistance with parts or information.

Pat

Until I finish the kits for the 1960-66 valve bodies I have just the 2 OEM part-throttle types on the Store, applicable to 1967 & later. The simple early type was originated in 1967 on the Slant 6 904 and continued in many of those applications up into the 1970’s. The more complex type was originated in 1971 on many models except high-performance.

Hope to have the new kits for the early years available later this week or the first of next week; waiting for some tooling.

Pat