Brad, there is probably absolutely nothing wrong with your engine. These mid '90's 350's are crap. I bought my '94 GMC k1500 about 3 years ago, a one owner, always garaged, always maintained 130,000 mile creme puff to tow our 5,000 lb travel trailer. Wouldn't even go 65 mph running solo. Did discover while the owner changed all the fluids regularly (got the CarFax) he never changed plugs, cap, wires or rotor. But that didn't help much. After avoiding some mountain passes and driving in 2nd all day against a headwind in Nevada (6 mpg) I got ticked off and started making some changes. The best thing was to get rid of the very restrictive air intake box that reduced the intake from 4" to 3". Got rid of the choke aparatus and replaced it all with a 4" dryer duct going directly from the fender to the air cleaner. Helped a lot. Have since added a second air intake coming from the other side. Added an adjustable timing control from MSD, helped some. A little better but still a dog. Next best thing was intalling dual exhaust and getting rid of the cats. That was a big improvement, but still underpowered, had trouble going over 40 mph up mountain passes, lots of them here in the west.
Going up these passes in 2nd gear at about 3700 rpm began cracking exhaust manifolds. So far have cracked 4. So after putting up with no power I bought and installed a 383 stroker from S&J Engines in Spokane and that solved the problem Those things have so much torque I can pull in 4th most cases but I don't too much as it might ruin the weak 4L60e tranny. Put a bigger cooler on it for that purpose.
Guess what?, just got back from Eastern Washington and 100 degree heat with another cracked manifold. Had enough of that, headers will be here tomorrow. The only replacement exhaust manifolds you can get these days are Chinese or Vietnamese, pure crap.
So, as I said, probably not that much wrong with your engine, it is just a underpowered boat anchor. The 383 was only $2300 with roller cam and help to install it. Had to have the chip re-programed by Old EFi on this forum.