Time for a new machanic .
http://www.car-stuff.com/mmparts/dod..._manifold.html
Same block as the 318, just a little bigger. And balanced inside not the outside like the 318. Put some 340 heads or the Mopar swirle port heads on that thing or the w5. I loved my old dodge. I could sit on the fender and work on it. Change and altinator in 5 minutes flat. So much room, so many problems. My first one had 160,000 when I left her.