Wow, thats something I hadn't thought of, machining in screw in caps! A friend was recently concerned that the Cobra he bought might have a 390 (seller said 427 side oiler, "rumor" has it might be a 390). I didn't have a lot of time but checked for the screw in freeze plugs and they were there! Based on that I said it's most likely a 427, will have to check further to see if it's side oiler.
Now I'm worried it really COULD be a 390 "converted"! The motor also had the cross bolts, but now I guess I can't rely on that either!
