260 intake port question

[Sharpie]

I have the head off of my ms260 I have already opend up the muffler, now and am going to mill .015 off of the jug, and widen the exhaust port out to within .040 of each side the skirt. Then I am going to raise the intake port .015 to match up to its origonal position. Can I open up the intake port to a round hole shape where the rubber intake clamps on? Rite there at the start of the hole it is shaped like a "D" it looks very constrictive. Do you guys ever put in a thinner head gasket instead of milling the jug? This is my first attempt at this and I need lots of help.

 

[Crofter]

Thinner or no gasket is used. dont be quick to take the top of the intake port up. The important (timing) side of the intake port you have changed by machining the jug is its bottom. The top of the port has no impact on intake duration and little on flow. If you later on decide to take the jug down further and dome the piston to raise compression you risk uncovering the top of the intake port if you remove material there now.
Re the intake port nozzle. Only remove material to match it to the id shape and size of the intake boot. An increase in size that results in a sharp transition will hurt you more from induced turbulence than what you would seem to gain by the bigger hole.

 

[Sharpie]

Thanks for the help