Well I did a test for the heck of it today....sorry...no pictures or video. Anyhow, I towed my 1947 Case VAI and that was loaded on a double axle trailer....so the load wasn't light....Bout 6000+ pounds. Well...I really hate the SM420 for towing applications because when you go from 3rd to 4th shifting at 3000 RPM things drop to 1500 rpm and pulling a slight grade things pretty much Stay there. lol I was at half throttle and slooooooooooooooooooooooooooooooooowly picking up speed. Good thing the highway leveled out. haha But on flat ground getting up to 55 no problem at all. GOOD torque in the low range....motor had NO problem at ALL pulling from 8 MPH in 3rd gear...bout 900 rpm lug if I remember right. Starting on Flat ground...rev it quick in granny then shift to 2nd and shift at 2700 rpm into 3rd then at 2700 rpm into 4th and sitting at around 2500 going down the highway...which was around 50-55. On a slight incline I would shift from 2nd to 3rd at 2700 then 3rd to 4th at 3000 and keep it half throttle the rest of the way. There was a hill I pulled in 4th no problem....bout 40 mph and hill ended before I needed to downshift. Motor has some guts for its smallish size as far as cubes go. But a gear vendors OD I think is needed now. Mainly to have something between 3rd and 4th for towing cause the engine hates that drop. I'll say one thing...I'm sure the 4 barrel and split exhaust helped a ton. lol If I ever run across a 478 I think I won't be able to resist a swap. LOL! Love my 305 v6 though! Good running engine...did what it needed to do with no problem and pulled hard with no complaints. She's a runner.