Cheepy Three-Sixty build

400 is possible with that small camshaft, using 1.6 rockers (.480/.510) and having the heads work well.

Intake tract is the make or break on this one for 400hp

You're reading my mind,definitely going with 1.6 rockers and the heads will be worked for a flow rate of 230-240 cfm with a strong .300-.400" being of primary importance. I may have to break the bank on the valvetrain-but it should illustrate nicely of where to invest your $$$. J.Rob