I have a 1987 GMC R3500. TBI 350, TH400, 4.56 gears. I am looking for more out of the engine. I realize that TBI is not ideal for making more power but I want to keep it as much original as I can as the rest of the truck is basically as it came from factory. I mostly use the truck for pulling trailers. I found a used Edelbrock performer 3704 intake. Looking for suggestions on fuel modifications, which cam to go with that will work with the TBI system, and what kind of machine work could be done to the stock heads on this engine? Not looking to drop $500+ on vortec heads. Any other tips and advice is appreciated. Have been away from this website a few years, glad to see it's still seeing traffic!