My friends 351M/400 was bored .60 over and had the oversized pistons to go along with that. Double roller timing chain was put in it, MSD spark box and dist were also added to it. He also had a holley 4 barrel carb on it with a Edelbrock performer alum intake. He had some kind of radical cam in it (Not sure if it was Comp or Lunati) Not sure what else was done to it, but I know the final compression was around 12 to 1 once it was done. The only bad thing he did then was to run reg 87 pump gas in it and that was bad. Truck was run for about 5 years before the double roller chain had streched real bad causing it to run like crap.

It all depends on how much money you have and what you want to do with it. I know in another forum (Bronco site) alot of guys like to put Aussie heads on the 351M/400.

Oh and no matter what you do, install a high volume oil pump. To gain a few extra horses also, run an electric fan instead of the motor driven fan. And I would also find yourself a fuse panel that can handle 200 amps and get a 3g alt for it as well.