Fixed! Is your 6.9 totally gutless? Mine was until...
 

For the benefit of others:

My 1986 6.9 was gutless. Completed unloaded it could barely do 55mph up a nearby 8% grade. I never really watched the speedometer because my truck was just slow. I stayed in the slow lane; let traffic pass me on the 2-lanes...I was just the slow old truck. I had replaced every part of the fuel and ignition system and that almost entirely eliminated the clouds of smoke I was leaving everywhere...but nothing improved torque or speed. I had resigned myself to the assumption that the 6.9 was just a weak engine.

And then I blew a head gasket. So I had the heads rebuilt and put it back together. (By the way, a head gasket that is about to blow out will create a strange "paper sounding" tick in the engine. Kind of like cylinders with no oil but the ticking sound seems more like paper than metal)

And now...

WOW!

IT'S A COMPLETELY DIFFERENT TRUCK! I now fly up that hill at 75mph if I'm not thinking about it. My average cruising speed on the highway at 2500rpm in 4th gear went from 60 to 80. I now have to intentionally reduce my speed and be careful about speed limits. :-jammin

Not a single repair to the truck has left a greater impact. It was a pricey fix; but man was it worth it. I finally have some decent power out of this thing!

Also, beware: More power can create more problems. Due to that power improvement I quickly burned out my old clutch. Undesirable, but a good problem to have. :D

New gasket and head rebuild FOR THE WIN! :-X22

Put a turbo on it, you'll think its a stock car, haha.

don't get too exited,or you'll want to pull the other head and refresh that one too.:)

I dare you to put a Banks Sidewinder or ATS Aurora 2000 on that thing and then try and fly down the highway lol.

Man I can't wait to freshen up my 7.3, it's gutless as heck, to much mileage on the original IP.

The 6.9 has a fresh fuel system, and low mileage, but it's never going to be quick, it's been hauling a house on it's back since new! :D

YOu and your vans....jesus john lol.

Hey hey no hittting on the shaggin wagon :D



I wish! haha

my '87 6.9 has never been a "fast" truck, but I have been running an old ATS turbo on it for nearly 300,000 miles. It may not cross the finish line first, but it will pull a freight train across America. I'm on my second clutch. Need to do the same head work you did!