300bhp N/A on an early model 1uz-fe SC400/LS400/Soarer motor...
1) BFI intake
2) Mild Cam upgrade
3) ECU piggy-back Safc II
4) Exhaust upgrades, headers, pipes, high flowing mufflers, no cats, etc...
300whp N/A
1) Cams big lift....
2) Eight throttle body intake
3) straight pipes with headers....
4) Stand alone ECU tuned to perfection
300bhp N/A without cams...Maybe, not sure...(approx..240-250whp)
1) BFI intake
2) ECU and perfect tune
3) Headers and 2.25 mandrel full piping and or straight pipes, no cats, straight thru mufflers...
4) Complete engine electric upgrades, including Electric fans...
5) Delete all engine crank drag.. PS, Hydro pump, A/C...Alternator only..
6) Seafoam everything
Still probably won't get 250whp...But will be close...
Or as Smitherz mention... Nitrous system... Try swapping in a strong torque converter, that will give you the illusion of having 300hp at launch...0-30mph...