1988 Toyota Pickup Loss of hiway mpg, sluggish performance

Hello,
I rebuilt the top end of my 22R engine in my 1988 Toyota truck 4500 miles ago. It included a new head, new RV cam, new valve springs, 4-angle valve job, new head bolts, new timing cover, new timing chain, new cam sprocket & crankshaft sprocket, new timing chain rails, new oil pump, and a new catalytic converter.
I have had the valves adjusted at a local Toyota dealership. The engine idles with 19" of steady vacumn(900' elevation). The idle is very smooth at 750 RPM, and the compression is #1 cyl.-174lb, #2 cyl.-175lb, #3 cyl.-175lb, #4 cyl.-180lb. On a cold engine. All spark plug leads check out with about 0.5 Ohms of resistance. Plugs are NGK #BPR5EY.
I rebuilt the carburator about 3 years ago and it was giving outstanding mileage(31 mpg hiway) prior to this engine rebuild. The engine uses no oil between oil changes.
Here's the problem: #3 spark plug on multiple examinations is always coming up way richer than the other 3, even when I have switched it's position in different cylinders. I have lost 5 mpg on the hiway. The engines performance seems doggish as compared to the factory standard camshaft. I have tried 2 different ignition timing positions: 2 degrees BTDC and 7 degrees BTDC. The factory setting is suppose to be 0 degrees BTDC. At this setting it is a very smooth idle, but it is also very smooth at the other two settings. Even at 7 degrees BTDC I don't notice any pinging on hard acceleration on hills. The distributor has the 2 vacumn line setup. I talked with the machine shop owner where I purchased the new parts about this problem and he said this is not the usual scenerio with the RV cam in the 22R engines, as most people have reported slight mpg gains and better performance. Thank you.