To safely tow a trailer, in addition to your brake controller, find a
Class III hitch that will fit your FS Pontiac (maybe look for a late model FS rear drive GM) or a universal fit.
Then use a Equalizer Hitch setup. Referred to in another post as "Load Levelers". This elimnates and need for rear spring change or blown out bags
while towing! The Eq hitches are avail on eBay with different capacities. You would want the 600/10,00 lb on. That is spring bars for 600 lb tonuge weight and 10k lb towing. The spring bars allow you to distribute the weight on all 3 axles and lower you rear fenderwell clearance only 1" with trailer loaded.
The images below are of my '93 "TowMaster" wagon with factory 5000# tow package (and the auto level system eliminated) and eq system hooked up. It has a 5.7 TBI (190 HP), and 3.23 rear end. I tow a tilt bed trailer 2000# empty with the GTO on it.
DanC