I have a 406 (bored 400) If it was up to me, I would just do a good rebuild, using the stock parts. (He said he was not building a race motor). use the cam for your needs, (I run a 221/230 @ .050 for 9.5-1 to 10.5-1) , almost any head will help, almost! (I hear most 400 sb heads are cracked!) I run 305 heads (custom milled 58cc & 2.02 valves), but, I wanted to raise my comp. and a drilled Q-jet. Runs strong, and it's quick off the line. 400's are good low rpm torque motors stock. So build it around low end torque, not high rpm's (beat them out of the hole, and let them try to catch up to you!)

Use the head gasket to mark where to drill the steam holes.

Three years pushing my '68 El Camino around stacked at times higher then the roof, 365 day's a year, 100+ to -40 it takes me 20 miles to work, and no problems!

Pat