I did weld up an M1 like that for a 383. Used it on a 451 stroker. Ported 452 factory iron heads, 950 cfm Quick Fuel carb, $45.00 2" spacer off eBay, 9.5:1 compression, Comp Cams XR292R solid roller. 588 lb-ft @ 4,600 rpm and 621 hp @ 6,100 rpm. All this back on March 3, 2006.
The dyno operator says, "How the hell does that little engine make that horsepower with them little tiny Mopar ports?"