Calling one car that uses a different aspiration certainly is not unfair at all.
If anything a 5.0 should be running 295s. A GT500 should be going in the 335s if not 345s, SS versions should be at 355s. And a stickier compound. Compared to similar powered cars like a Viper and MP4, Those cars have bugger stickier tyres, along with being a lot better geared, and have a lot less weight( Along with more electronic interference for the MP4)
I wouldn't buy the Z/28 either, Seems WAY overpriced, DOUBLE the price over a 1LE? The Fuk? Shouldn't have past 60k Usd. It wont perform better acceleration tests then a GT500, But will kill it round a track, And 54k is not what I would call everyone can afford, Not even in the USA. That's slightly above average.
About the GT, I would not want that back, I think a Ford GT/GT40(Should have called it GT43, Should be one of those cars that should ONLY appear during a certain timeline, Or every so amount of years, Like how Ferrari does there Super Ferraris. If they did bring it back, it would certainly have Bhp over 670Bhp.