Cant put 24 Valve heads on a 12 Valve block there are minor differences with water jackets. Best bet to do this is get a wrecked Donor SR with 3.5 or maybe a later model 95-96 LS with the SOHC 24 valve if you want to stick with 3.0 displacement. You'll need to get the brain and wiring harness from donor...

99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..