D2 is right, To get the full benefit of the overdrive it's often necessary to swap rear gears top optimize your acceleration and economy at your normal cruise rpm. Installing a Gear Vendors without changing the rear gear WILL NOT be a problem. They actually have a kit they call "gear switching" where the car shifts automatically through the gears 1st-1st od-2nd-2nd od etc, like a 6 speed. I don't think a healthy 440 will have much trouble pulling the car with almost any gear. In my 3800 lb 4 speed I am often in 4th around 20 mph and the car doesn't lug unless you try to accelerate hard. With the automatic feature it should select the proper gear anyway. I don't see how a lock up 727 would be a problem, although it might not be worth the trouble of swapping the trans. There is a Mopar 4 speed auto (A518) which is basically a 727 with an extra gear. I'm sure it could handle the engine and you can buy them new (but pricey) from Mopar Performance. The problem is that the o/d adds length and width at the back of the trans. Extensive floor pan/trans tunnel mods are required on an A-body. I don't know of anybody doing the mod on a c-body or Imperial. Rob At work, dreaming of adding o/d to my 300 hp '83 Imperial, but first let's get it running WITH a/c. _________________________________________________________________ Let the new MSN Premium Internet Software make the most of your high-speed experience. http://join.msn.com/?pgmarket=en-us&page=byoa/prem&ST=1