I recently did a cam swap on my 69 383. went from a 284 to a 268. Car ran fine for a couple days and then it started running rough and the pcv valve is rattling like crazy. I checked for intake leak and found none. I checked vac. and got about 18 but it is not steady the needle shakes a lot. I tried moving the pcv hose from the front to the back of the carb and it seemed to geta little better but still surges. I have heard from friends and relatives that this is the best place to get good sound advice, so thank you in advance. Jim