Originally Posted by xntrik
Generally speaking =
the C is considered a small block.
the M is considered a big block.
Because that's the way stuff bolts on/ engine mounts and trans, etc. (the C and W use the same stuff)
Several good places to get stuff for FMX. Good trans, just cast iron case/heavy.
Where are you going to find a small block FMX bellhousing?
I'd just drop in a C-4 with the C and let it go at that.
If I were making the decision, I would go for a W with a C-4 (unless you can find a small block C-6/rare.)
(a 460 will shuck that FMX quick, you'd need a C-6 in two days)
My experience and opinion is that an FMX will take a way more abuse than a stock C4. I'm pretty sure that they also used the FMX behind the 390/428 FE in the 65-68 full-sized Ford and Merc, didn't they? I always thought that it was the "big transmission" until the C6 was introduced.
I had a 66 Galaxie with a 289 and "cruise-o-matic" (pretty much the same as FMX ... just a different valve body, I believe.) I replaced the 289 with a stock 1971 351C-4V. I drove the snot out of that car, and did eventually burn out the FMX at around 85,000 miles. A friend had a recently rebuilt C4, so we put that in ... and it lasted DAYS. I found another used FMX from a 66 Galaxie convertible behind a 390 and threw it in. It outlasted the differential which was the last thing to go before I sold the car.
The biggest complaint I ever had with the FMX was (as I said earlier) the convertor stall speed. It was just plain embarassing. The "legendary" Cleveland WOULD NOT move that Galaxie up an incline, (Just imagine the abuse I took from my buddies!) and I never raced from a standing start if I could help it. But at 25 or 30 MPH in low gear ... watch out!
I agree that the C6 is best suited for either a 351C or a 460 as that is what Ford usually used when they installed them. IF you can find a small-block C6, try to get the factory 2500 RPM stall convertor that were used with the Cleveland in 70-73 Mustangs.
My second "Cleveland" car was a 1968 Torino with a "built" 351C / C6 / 9-inch posi drivetrain. I took that C6's front pump out a couple of times before discovering that the dowel holes were oblonged and putting a LOT of stress on the pump. Shortly after fixing the transmission, the car was stolen ... resulting in a broken driveshaft, a hole in the floorboards, and a 3-piece (exploded internally) transmission!
If it wasn't for bad luck, I wouldn't have any luck at all!