2 port to 3 port question

[oldscooterbloke1]

Hi, do you know if a 3 port barrel will interchange  on to a 2 port 150s series 1 VLB1m engine.
most tuning kits seem to be based on the 3 port kit.
there looks to be enough meat on the case to open up for the 3rd port as its small, do the studs line up / the same spacing as with a 2 port. 
Looking to get about 15 to 20 bhp from a kit and porting.carb and exhaust.

[adrian]

3 port engine is the way to go, but pinasco do a 2 port 177 kit

[oldscooterbloke1]

thanks, what power is that kit do you know?

[adrian]

Sorry I have no idea what power, but should be able to tune more out of it,