73-87 Chevy front end shaking...

Well finally Im stumped, my 79 shakes at 40-45mph with a death shake. Its fine to putt to work in but I cant roll the freeway. I cant seem to find anything wrong with it. Ball jints, tie rods, Pitman and idler and all the other steering components ar fine, not loose or worn. Allignment was done and tires were rebalanced. Still it shakes so bad. Wheels are not bent and adapters are not tweeked. What is the issue? Any of you guys runnin these trucks have this issue before? Any of you guys have to run a stabilizer when switching to Semi's?

Have a 79 with no issues up to 70mph. Did u run it w/o stabilizer installed? Maybe remove it....not sure if it will matter juza thought

i just finished mine and it had a minor shake first time i test drove and rode low....added the shocks and it went away....also make sure your rims arent wobbling and true centered....easier way is jack wheel off ground and slide a spray paint cab right up beside tire and spin tire....you'll be able to tell real fast....also when they balanced the tires did they do it with the adaptors bolts to rims or just rims and tires