[Bill D]

Rune
I can understand your desire for being as original as possible. A 289 can be made to produce 390 HP but it's going to take some work. The reason for forged internals is more for reliability than anything else. You'll need to push high compression which means forged pistons (for reliability).

Cam selection for Webers is critical since Webers don't like a lot of duration and overlap. They like a high lift short duration cam

Where are you getting iron heads?

Bill