High Performance 318ci

Guys, firtst of all, plan is to build a small block and keep it 318ci to make things more difficult ;-) So no big blocks. The owner of the car wants 318ci.
Too many changes to the drivetrain to put big block in it and also zero big blocks for reasonable money where we are located.
I am surprised that so many people are against 318, buddy of mine is constantly wining autocross events in his Challenger with 318 (roller cam, ported iron heads and 410hp). Challenger is not feather light either.

For the wagon I was thinking to get very good heads but stay with flat tappet cam, get some compression, put rather small cam that has lift to take advantage of these heads flow etc... Operating range of this cam is 2500-6200 rpm.
Regarding too much carb, well given the power goal, I would never say that 750cfm is too much. Six pack on 340 is what? 1250cfm...? Also less power.

So really you all say that 318 is a lost cause? I was hoping for more positive approach.