Good Morning from Central Arkansas....I'm working in a 70 Plymouth Satellite,I'm needing to change the gears ..it has currently a very worn sure grip with 290 something( please forgive my forgetfulness here) and I'm wanting to put in some 391s( not sure grip) ..and although a Mechanic of many years..have never opened up a Mopar third member..but I was told that my 391s wouldn't work in my current 3rd member...If more Info is needed for help..let me know please..thank you ...Dan H
