[scottj]

agro1,

No, I would go so far as to say that often for a street engine. Look at Hal with 50K on his engine and I'd call that street high-performance by most standards, plus he does track events as well.

My race engines follow a typical maintenance schedule for the type of engine and most people wouldn't call my "street" engine a street engine, nor would they want to run it on the street. Realistically, I could get away with changing springs and lifters only on the street engine. The best preventitive maintenance, IMO, is build it right and for the intended application. I built very well, but in the case of the Cobra, not for the application and now I pay the price. For example; unless you really don't mind changing springs and roller lifters that often, don't run a roller cam with 266 deg Int and 272 deg Exh duration @ .050 w/.700 lift.

As far as freshening intervals base on miles vs. the level of abuse; according to my builder, springs and lifter replacement is according to mileage (or laps) and bearings and rings are according to the number of heat cycles (times run). Freshening is cheap insurance for the race engines since after 20 nights or so you begin gambling with the entire investment. The Cobra engine is MUCH less of a gamble because it doen't get the amount of abuse in a year that the race engine gets in a night, therefore it's less likely to fail.

Basic "freshening" is rings, bearings, hone, lifters, springs, timing chain set, gaskets, & wet-mag. But the race engines always need other stuff like a cam, decking, valves, plug wires, etc.