Most B-bodies in 1984 had the 700R-4 transmission. On occasion you found a metric 200. For your answer, let's assume you are running a 700R-4. The simple answer is no. You cannot easily change the shift points on this transmission. There is no modulator valve adjustments available on this transmission and the transmissions were not computer controlled until 1990 when it became known as the 4L60E. If you are not concerned about having overdrive, it would be fairly easy and inxpensive to install a THM350. You will need to find a long tail unit out of a 2WD truck or a 72-76 GM B-Body. (You are looking for a 9" tail shaft.) Also be sure to make sure the bolt crown is the same. Chevy is different from all other GMs. You will need to either move your crossmember forward a few inches, or you will need to fabricate an extension plate to bolt the transmission to the crossmember (which is what I did). You will need to purchase a kickdown cable for a 77-79 full size GM with a 4BBL Carb. Minor fabrication may be required for the mounting plate for the kickdown cable on top of the intake, or you can pick one up at a salvage yard for about $5.00. It is critical that you get one for a 4BBL and not a 2BBL because the positioning of the cable is different. If you can't find a long tail transmission, a third option is to find a drive shaft from a 77-79 Wagon and use a short shaft THM350. Swapping the transmission will give you much more flexibility in shift points because you can adjust the vacuum held by the modulator valve via the set screw in the end. It will also give you much more reliability as the pre-1988 700R-4 transmissions were not very good. One down side is that the THM350 only has like a 2.76 first gear whereas the 700R-4 has a 3.08 first gear so you will not launch quite as well but for a daily driver, that shouldn't be an issue.