Hello,

This is the plan of action you need to take for 250 CRANK HP.

1. Single Intake
2. Fuel Injectors
3. ECU Remap
4. Higher Flow Exhaust (Dual)

That should get you to 250 crank very easily.

250 RWHP is about 300 CRANK HP.

You will need a different intake manifold, cams, and headers to even think about those numbers with stock displacement.

Good Luck!

Anthony
TVT Design