What camshaft/converter/gears for Cleveland

[Unit 5302]

I wouldn't build the 400M, either. If I did, I certainly wouldn't be revving it to 6000rpm. The engine has a very long 4.0" stroke which really increases the piston speed and stress on the rotating assembly. Make sure your transmission will fit, too. To accomodate that stroke, the deck height of the 351 was raised, and the rods were made longer, and very few 400M blocks actually have the same bolt pattern as the 351C engines.

You're going to be limited to around 5000rpm for peak power.

http://www.tmeyerinc.com/400Fordpg4.htm