Thanks Homebrewz. My 81 had the 22R engine, but some still came with the 20R (I think). Some people swapped a 20R head onto the 22R block for higher compression and HP, never tried it though. If I had another it would be the 22RE - I had an 87 that was a great truck and could actually go up hills a little bit. The 22R was a bit underpowered at 7-8K feet.
Loss of power could be anything, but vacuum lines on those are a possibility, especially if it sat for a while they'd dry rot and crack when you start driving it again. You can just by cheap vacuum hose at NAPA and replace one at a time (or keep really good track when you disconnect them), it's got a whole bowl of spaghetti in there and a vacuum pump that runs off the engine. I just disconnected random lines til it ran better, but there's a right way I'm sure. If the compression checks OK then there's an aftermarket Weber carb that does away with a lot of them.
Loss of power could be anything, but vacuum lines on those are a possibility, especially if it sat for a while they'd dry rot and crack when you start driving it again. You can just by cheap vacuum hose at NAPA and replace one at a time (or keep really good track when you disconnect them), it's got a whole bowl of spaghetti in there and a vacuum pump that runs off the engine. I just disconnected random lines til it ran better, but there's a right way I'm sure. If the compression checks OK then there's an aftermarket Weber carb that does away with a lot of them.