An AT6 Pilot flying an aircraft with advanced navigation equipment failed to set the altimeter correctly before takeoff and exceeded his assigned level off altitude by 600 FT before ATC gave him further climb clearance.

Narrative

Climbing out on an IFR flight plan via radar vectors on assigned heading 270; my assigned altitude was amended from 3;000 FT to 4;000 FT. The Controller asked what altitude I was showing as I went through 3;600 indicated. I replied; 'Climbing through 3;700.' The Controller indicated showing me at 4;700 then said; 'That's OK; just climb and maintain 5;000'. There was no indication of a traffic conflict; nor did I observe any other traffic. My PCAS traffic alerter showed no traffic within 5 miles. Under scrutiny; I found that one of my two altimeters was set one inch off from the proper altimeter setting. I corrected the error; leveled at 5;000 and continued the flight without further incident. The aircraft has an EFIS; a mechanical sweep hand altimeter; and an MFD which all have to be set to the altimeter setting. I had apparently misread the setting on the sweep hand altimeter when setting them and had not noticed the conflicting indications while climbing. Contributing factors: The aircraft had been flown in an air show performance the previous day and the altimeter had apparently been set to zero feet AGL prior to the flight. The altimeter was still at this setting when I set it up for the ferry flight. Also; less reliance on all available equipment during a busy situation could have defeated the redundancy. My eyes were drawn to the most familiar equipment because it was easier to read quickly. My recollection is that the altimeter setting was 29.87 and what I discovered the altimeter in question to be set at was 28.87. The visual similarity between the two settings may have contributed. Had I scrutinized the instrument closer; I would have recognized the error on both the setting and the altitude indication compared to field elevation.