Raising the ports sky high on oval port 56

[filthy phill]

I know many people talk about raising the ports to 56 spec bla bla bla
But what would happen if the port was taken up a bit more ?
like take the roof of the exhaust up another 10 thou and then taking the port to this height then a chamfer.
this would be about 20 thou higher than the sst60 porting I know, but due to the oval not being as wide as the bridge would give a bit more exhaust area.

or what about if take the port all the way to the roof plus chanfer then put a v notch like seen on same Yamaha v4 motors ?

what would these type of things actually do to the powerband ?

this type of notch on the exhaust port is what I mean below, I saw this on another forum and its been bugging me what it would do.
I have not seen this type of thing before so have been trying to find out what the effects are. ?

[Per]

I ASSUME that the notch is there as a idle reliefe.

[filthy phill]

Yeah it could be idle relief. Would of thought it would be a bit higher up for that like the omc.
Those oval ports also look a bit big on the yamaha.?

[TNT Teen]

The worst thing to do when porting is raising your ports too high in too big a step. Raised ports moves the power band, you move it too high and you'll just bog like crazy trying to accelerate. Its easy to remove more metal, then trying to put it back. You can also file the edge of the piston sine that is what controls port opening/closing. Pistons are cheaper then a block

[filthy phill]

definitely would not file any pistons.

just take it to the roof of the exhaust then.

[fs5]

That's a decompression port in the sleeve. Some guys weld them up to increase compression. You can flute the side of a piston to open the ports earlier. Google it there's some pretty beet pics of what people have tried

[filthy phill]

well I wont be putting any v notches in mine then ha ha

[fs5]

Stupid spell check on phone...
I ment sweet as in good