I agree with what you are saying about the heads.
Since I started in 1980, MoPar guys have bitched about the cost of rockers. This I know. The W-2 head will out perform ANY 23* standard port chevy head to this day. The W-% head wil outperform any 23* chevy head in raised port configuration to this day. I wouldnt even consider a 400 CID small block without W-5 or better heads. Ever.
You have to spend some $$$$$ to make horsepower. It blows my mind why anyone would buy that bigmouth head. It will never run with a W-2. It still requires offset rockers. You have to move the pushrod. Its that simple.