The static compression ratio is 8.7 and dynamic compression ratio is 7.47. Would a 4.0 tuned and modified like posted above benefit much from octane higher than 87?
The compression doesn't require more octane, but the tune may if you pushed the ignition timing up enough. I think a good performance tune in a 4.0 would be more timing and more fuel at WOT. The ones I have run on the dyno stock all seem to be a little lean and reasonably conservative on the timing.