3.0 Cracked Head

Dear Sirs,
I have a 1992 Ford Ranger with 3.0 V-6. Just replaced a cracked head.
The truck ran okay before the change except for missing alittle. It was obvious that the head I took off was cracked. After replacing the head, I tried to start it up and would not start, After holding the accelerator down and continually cranking it finally started, but it has no power at all, just barely enough to stay running with it accelerated. I double checked everything,firing order,timing,everything checks out. I did not turn the motor during the swap, distributor, spark plug wires were marked and replaced back in the same order. I had the same thing on the motor I robbed the head off of to replace this one. I checked the head out before I put it on it looked fine. Just a backyard mechanic here, what am I doing wrong?. could it be bent valves on the replaced head or warpage?. Any info would be greatly appreciated.

Thanks,
Gregg

only thing i can think of would be did you set valve lash correctly? check for vacume leaks around intake.