Ford Repair: 351C in a 71 Mustang Mach 1, mustang mach 1, carbuerator

Question
The performance in my new -old car is,... well, less than expected.  When I got the car it was horrible.   Sputtering all through the throttle.  My friend advanced the timing and the low end is quite a bit better.  We cleaned quite a bit of rust out of the carb, and that helped as well.  Problem is, it still takes power-braking to spin the tires.  It's got a 2V 351C 2bl engine.  Mid range through top-end is nearly non-existent (sputters up until shift point like it's missing).  My question(s) are, shouldn't this be performing much better?  Shouldn't I be able to break loose the tires on this car?  Could this be a carburation issue? (too rich perhaps?)  I'm probably giving in to easily, but I hear some really good about the engine, and then turn around and someone tells me to junk the 351C.  Any advice you can give would be greatly appreciated.  Oh, I plan to put on a new aluminum manifold and a 650cfm Holley carb (4 bl).  How much would this help?  (also planning headers as well.)

Answer
Rick,

In my opinion a 351C is better than a 351W, and it is one of the best motors of it's time.

It sounds to me like your biggest problem is your carbuerator. Putting on the manifold and carbuerator that you mention should help you tremendously as it is a very good combo. Once you do that combination change, put your timing back to spec and try it again. Hope that this helps and if you need further assistance, please do not hesitate to contact me. I would like to hear how you make out after you make your changes. Good luck.

Ken