I think the 90-95hp range is very achievable, 100+ probibly isnt going to be cost effective. Aaen exhaust, modified airbox (Ulmer racing), and a fuel controller is the easy stuff and should be 90-95hp. After that you need to port the head (4-5hp) and custom ground cams. to get you past 100hp. You can free up track HP though with a clutch kit, loose track, extrovert drivers, and setting the skid back 3" and installing a 128x13.5 AC track. I wouldn't want to do any mods that need increased RPMs to make power though as the rods are the weak spot in these engines and no one makes aftermarket ones. Quite a few turbo sleds have busted rods and I had one come through the case on my N/A phazer. Mine is the first naturally aspirated phazer to snap a rod with no cause, other have snapped from oil starvation.