I have a 1978 351M in my 53 ford sedan. It came out of a T-Bird also and it's a really good running motor. I put an Eldebrock Performer manifold with a 650 Vacuum secondary carb, used the stock exhaust manifolds (headers wouldn't clear steering box) with 2.5" pipes and turbo mufflers and a hotter coil. It runs good as the 53 is lighter than the old t-bird. All M's and 400's have the 2 barrel heads and they are all you need for the street, the problem with this motor is (as is with all smog motors) Compression. I intend to spend some time on this engine later when time is available, as for now it's a driver. My plans are 400 crank/rods, .030 overbore, 10.5 - 1 compression, crane rocker stud conversion w/ roller rockers, and a mid range hydraulic cam. The C-series motors have a lot of potential but the smog rules of the 70's killed them. The 2v heads are all you need for the street, the 4v's heads ports are too big to work well below 2500-3000 rpm's and that hurts you on the street.