If your sure your combo is healthy a stall should help alot. My car is 100% street and with a good converter running a 3,000+ stall should not be a problem. I was a little concerned myself about a higher stall on the street but it drives like a creampuff until you stand on it. The 3.91's with a 28 inch tire isn't terrible on the highway if you stick to 60-65, it does get buzzing pretty good over that though. My combo is just a little bigger cam, stall and gear more than yours but it sounds like worlds apart as far as performance, your sure theres nothing else wrong?