I am thinking the 445 has more HP.
Why would you want to get rid of Fuel injection?

 

I think the 445 is 22hp

 

They both use the same model number, And I do not want to remove the fuel injection as my engine does not have this on it

 

They have different flywheels, the 425 has 2 pulsar coils and the 445 only has 1. The pistons are different as well, but I don't think they would be an issue. As long as you changeout the pulsar coils, the flywheel and the wiring harness I think you will be ok. If Engine Tech comes by he can probably tell you for sure.

 

Convert a 425 to EFI? Anything is possible, and BVP above hit the high spots. But, it is far from worth it. You'd need the high pressure pump, lines, the intake, module, harness, etc and you'd get very little performance gain. The EFI mainly provides easier cold starting, auto-compensating for altitude, and modest fuel savings. If you found a junker 445, then maybe (as you could rob the larger wheels/tires, seat, and SCV couplers too). But otherwise, not worth it.

I'd keep the engine as it is, but the larger wheels/tires and seat would be worthwhile.

 

Can a longblock from a 425 be used to replace a bad longblock in a 445?