Overall these were/are a good engine and properly rebuilt should go well over 100,000 miles. As far a performance it will depend in large part on the heads. Late 54 was a change over year for larger valves that breather better than the earlier small valve units. The small valve heads can usually be identified by NOT having the water crossover passage in the front of the head and a "wet" intake manifold with the thermostat located in the intake.

Now a little dose of reality. If your going for visual impact I don't think anything beats the looks of a dressed out Hemi. If weight is not a consideration cubic inch for cubic inch it's hard to beat the Hemi head design for potential. In this case keep in mind you only have 331 CI (plus what ever overbore).

The 2 main sources of Hemi parts I have used are PAW (send for their early Hemi catalog) and http://www.hothemiheads.com/

You might want to spend a little time adding up what it will cost to go through one of these engines before you plunge in with both feet.