GM-GMC: lack of power, genuine gm, gmc pickup

Question
1979 GMC pickup.350 engine.half ton.2wheel drive.
motor lacks power on acceleration from stand still or going up hill.drives normal when it reaches whatever speed that i want to maintain.still drives up to 75-80mph smoothly with no problems.there is absolutely no smoke from exhaust pipes while driving, nor by idle.starts everytime by first turn of key.plugs,wires rotor,cap and carb are not too old.but motor has 130,000 on speedometer.

Answer
Henry - if you check my bio, repairs are not my strength.  However, having owned a few of these (and still have a 76, 78 and 86), you could be looking at a new fuel pump.

In buying a new fuel pump, I strongly recommend buying a original equipment genuine GM one.  The jobber ones have never lasted, in my experience.

If this fixes your problem, then don't forget to change the little fuel filter going into the carburetor every year too.  This helps for a long lasting fuel pump.

You don't say anything about pinging, but it may not hurt to pull off a valve cover with the truck running and see if all of the valves are opening fully.  Back around this vintage of truck, soft camshafts were VERY common.  If the lobes are worn, you will see this by the valves opening very little.  I had to do this to a 79 Sierra Classic I had.

If these repairs are more than you can handle, then off to the local garage, to see what they think.  Obviously, the fuel pump is the least costly and less messy of the two.  If you can find an old valve cover, and cut the tip off the it, this is a great way to not make a mess and check your cam.

Good luck,

Dean