So i have a 95 suburban thats SAS'd It has the 350tbi with a 4l60e in back. Just found out the intake manifold gasket is leaking so gonna replace that. I already did a full tuneup wires, cap, rotor, icm, fuel air filter, oil change, etc. Plan on keeping this truck a while so was looking at doing some modifications, looking to just increase mpg and free up some torque. I was either gonna drop some money into this motor, or look at buying a used 5.3 doing small maintenance and a cam on it and throwing it in. What would you do, main thing im looking for is fuel economy really. i know redundant on a sas suburban but anything helps. And as far as tires and gears, im running 38x15.5 with 4.56 gears right now, going to drop down to 35x12.50 and lower the truck a little just because its getting to tall