Updating to Modern Overdrive Part 1

RHEnterprises in Burbank CA recently embarked on upgrading the tranny in their ’70 Plymouth Scamp from a stock 904 to a modern 518 with overdrive (4speed) skipping the traditional upgrade route using a beefed 727 (3speed). The little Scamp is in the process of dumping its 45 year old 318 2bbl power plant for an earth pounding stroked late model 360 (post on the engine build coming soon). In Part 1, new trans mounts are mocked up, fabricated, and installed. 

  1. Set the tranny shell position. Used engine mount point as datum to back of engine for X & Z position. Center the trans in tunnel and figure the mods & crossmember.
  2. Cut out the factory reinforcement hoop out of the tunnel to clear tranny.
  3. Fabricated new 1/4 inch bar stock reinforcement hoop to clear tranny then weld.
  4. Designed and fabricated new tranny crossmember. 518 sits lower and mount is 3 inches shifted.
  5. Finished tranny mount. Hard rubber isolator 60 shore, $7 out of McMaster Carr.  Slots & isolator design allow for 2 axis final adjustment once engine trans combo is installed.


One comment

  1. r. heap says:

    Wow, great update & PR for this RH Enterprises outfit. They should hire Car Chunter to do all their PR! This project sure is ambitious. I think I had read in a different post they will be using an engine vacuum & trans pressure sensor setup from PATC to control the Lock Up Converter & Over Drive of that 518. The stock circa 1995 Mopar trucks used the ECM to electronically provide the commands. That setup is suppose to get rid of the need that most guys try with this conversion to run toggle switches to on/off those features. I think it is adjustable as well to adjust the RPM.

    Anyway, Nice Post !

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