When gasket matching how smooth does the area cut have to be? Can I leave it as cut with the carbide burr or do I need to hit it with a sanding roll? Thanks

Depends on how good you are with the burr! You want an open flute style burr for aluminum, although some single flute carbides can work for lighter work, and you'll want to use some lubricant ( usually wax). As far as the finish, on an intake port, you actually dont want it super smooth, as you really need to get the air and fule mixing, without casuing fuel drop out ( droplets). the coarser finish of a 40-80 grit cratrridge roll usually will help. One of the problems with porting, is that customers WANT to see all the shiny, mirror finish looking ports, when in reality, they arent realy the best. ( better on exhaust usually though)

Maybe one of the full time porters will chime in and expand some more.

Bump

Are you playing with alum or iron heads... I hit either
with a sanding roll to finish but dont make it smooth

Wow, sorry I completely left out important information. I put on Edelbrock heads last summer. I'm just trying to smooth out the transition between the M1 single plane and the machined openings in the heads. While the thing is apart should I also open up the top plate and get ride of the spread bore protrusions to square it up, or just leave it? Thanks guys so far.