Modifying bottom of the sleeve

[lorinlewis23]

What are the benifits of modifiying the bottom of the sleeve. Under which ports should be modified and why

 

[lorinlewis23]

What I mean is that I have seen sleeves modified with a semi circular cutout on the bottom. Why is this done.
example

 

[scrogathon]

The sleeve is cut in this manner to aid in fuel delivery, it helps the fuel get from the crankcase to the intake ports with less in the way, it may look fancy and all but this cut alone doesnt give all that much power, Most if not all power is found in timing changes that take quite a bit of skill to get right.

 

[lorinlewis23]

thanks for the info