[bobcowan]

In a nutshell: you have a good engine built by a pro. Tuned by a pro, it made good power. Now, some time later, it was tuned by another pro, and it did not make good power.

So, the question is: What changed? Something broken? Something failed? PO changed something, like the cam?

Time for some serious investigation to find the answer to that question. I would start with these things:
- basic tune up: plugs, wires, cap, rotor.
- pull the valve covers, and check all the valves and springs.
- adjust the rocker arms, again.
- compression check, wet and dry
- leak down test
- coolant system test, rule out a bad head gasket.

Careful diagnosis now will save time, money, and frustration later.