The fuel pressure is way too high. I think the electric fuel pump the previous owner put in is for a fuel injection set up. I went from 7 to 10 mpg. thats a big difference percentage wise. Now I think I will stay with the 361. My goal has always been to get 10 plus and have a big block. now maybe time for a nicely tuned AFB and dual exhaust might squeeze a few more MPG out of it. The muffle on it now is a massive dual in single out. almost 4 feet long. will either dual it out or get a higher flowing version of whats in there now. Like a Shuttleworth. they make the best mufflers.