You'd need to send the engine to Lenco or some other engine shop who could balance and blueprint the engine to very high tolerences. Since it's a 2.3 N/A engine, getting extra revs would help make more power, but you'd need substantial upgrades in the areas of the intake, higher compression, porting/polishing, lightest rotating mass, and efficient exhaust. The B-series of engines just wasn't designed to rev very high (relatively speaking).
I think the c900 rally cars with 2.0 8v N/A engines were built to go to 8000rpms or so, but that's with a full team to support the car. You'd be spending a ton of money for something that wouldn't be very streetable.