I have a 94 Ranger XLT 4x4, manual trans (3.0 V6)
The motor seems to actually have decent power, but at low rpm (usually 2k or below) and there is load, like starting from a stop, or lugging it, or climbing a hill, etc, there is a loud clacking/ratting noise and the engine dumps lots of smoke. Also, if I just drive it hard (lots of throttle and/or higher rpm) it will smoke, but not as much. It also goes through oil kinda quick, and its definitely blue smoke (indicating oil obviously).

Basically the only way I can drive it and it doesn't smoke horribly is to over-rev and slip the clutch gradually, when starting from a stop, and then just drive it real easy around town.

I just did plugs, wires, cap, and rotor, which seemed to help a lot with the general performance of the truck, but not the smoking.
I also did some seafoam in the gas, then a direct intake seafoam treatment later, but it doesn't seem to have done much.

Is this a sign of the rings being shot? Or could an experienced shop probably fix the problem for under $500?
I know everything about Subarus mechanic-wise, but nothing about trucks.

Thanks