Ive got an 89 F250 with a 351w speed density. I'm looking to get as much torque as possible between 1000 and 5500 rpm. I will be swapping to Mass Air and I was wondering what heads, intake, and cam will give the truck the best results in building torque. Please help!!

 

Here's the deal, longtubes and a cam on the stock motor will make close to 400ft/lbs TQ from just above idle, no mass air conversion or any other parts necessary. Bigger heads and an intake will produce 20-40ft/lbs more peak TQ but it will also occur at a higher rpm and will definitely require mass air, larger injectors, a bigger fuel pump, and computer tuning if you want the full potential. The first option may only cost a few hundred dollars but the second one will be several thousand for sure.