Since I have a fixed rear end ratio (unless I want to go to the trouble of changing it-which I don't) I was hoping that the manual trans. I have might give me a slightly better gas mileage than the auto. trans. Considering the effort involved in removing the manual trans. and clutch pedal assem. from the parts car and installing it in my 450slc I doubt that the result will be worth the trouble. Gas here is about $1.50 a gal. and I doubt that I will drive the slc more than 5,000 a year so the difference between 14 mpg with the auto. trans. and probably 15 mpg with manual will not be a financial benifit. It will be an interesting project but not cost effective.