My 383 in my 70 Satellite is also a little lazy off the bottom. I think maybe just a bit too much cam in mine. I run 3.23's and have 275-60-17 rear tires. They measure right at 30". Last spring I put 3.91's in and ran them for a month or so. it helped it turn on sooner but it was exactly the same at initial start. I know it needs a converter, that would be the correct fix, but I am going to stay with the 1800 anyway. It runs pretty good from 2800 to 5500 or so.