The increase in power you'll see with headwork is marginal compared to increased boost. Since you have the supercharger already installed (I'm impressed: Never seen one on a "ix") you're almost on your way to serious power. Lower the compression (make sure you O-Ring the block.... I've seen plenty of M20 motors go through numerous head gaskets with boost) pistons would be perfect, but expensive. A thicker head gasket is okay, but mind the timing belt! With higher boost, you'll automatically get more torque down low so stroking it would be pointless unless it's a turbo application. If all the measurements are correct and your underdrive pulley is the right ratio to your blower pulley, you should get boost right from 1500rpm onwards. Since the head is off, it doesn't hurt to give it a quick port and/or polish.... good for a couple of HP. I'm just worried about your clutch and center diff. If you can put your car on a good interior weight diet, that will also help. Send pics!
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-- RANDY SPARRE --