[Jack21]

Trying to compare a 289 and 390FE is an apples-oranges comparison. Trying to get these revs from a passenger car FE block is asking for it. And tweaking this motor on a "Fun Car" to these kinds of revs will get you lots of tire smoke, and more money spend in legal fees defending your drivers license than machine shop fees building your engine.

If it doesn't have to look like an FE, a more reliable way to 427CI that will make HP and live would be a new aftermarket, 4 bolt Windsor block, forged rotating components (4.125 x 4.0), aluminum canted valve heads, solid lifter cam. Have your fun at the track.