I really like the project. Glad to see you haven't given up on it. Love that cross ram.
I hope you don't mind me butting in on your carb choice but I've seen quite a few 2 x 390 or 2 x 450s done on some smaller inch motors and they are underwhelming. Believe it or not even on a 355 a pair of 660 centesquirters or 600vs 1850s usually work better. I may be talking out my A$$ since I've never run a crossram on a Chevy. Just a thought if the dyno doesn't produce what you want off the bat try a pair of 1850s they can be bought cheap.
BTW in my opinion that is one of the all time coolest looking induction systems the factories fielded.
