I recently purchased a 1965 F100. The truck originally had a 240 with 3 on the tree, but a previous owner had put in a 300 and a automatic tranny (engine valve cover has a sticker with a 1977 date on it). When I bought the truck I was told the tranny was a C4, but when I went to install an aftermarket shifter today I noticed it's a C6. Now I'm contemplating changing it out for a C4. I plan to use this truck as a daily driver and keep the 300 engine. I'm thinking the C6 is a bit overkill and I'd benifit from the more efficient and lighter C4. Just wondering what people think of that? Should I keep the C6 or look to trade it for a C4?

 

You can't kill a C6, but it robs the engine of needed HP to get the tranny to move. It also drops your gas mileage some. I have one in my 89 F-250 4x4 and it's a pig on gas. I've got 120,000+ on it and I've never added fluid to it in the 8 years I've had it other than servicing it. The C4 is also a good tranny and will help on mileage and use less of the engine's HP. I wouldn't do alot of heavy hauling with the C4, but I'll bet those days are far behind. Don't expect that truck to win any races as that combination ( 6cyl + auto) equals a toad!

Barry