The Official Head Thread.

[Megadan]

Originally Posted by Baskt_Case

After reading through all of the linked threads twice, and corresponding with some professional head builders, I'm giving careful consideration to the squish band, or the "bevel" as its been referenced. I'll have 2 different gaskets to play with, and I'm going to talk to some more people before I settle on the exact amount I will mill off the head.

If you are chasing after an optimal quench gap (proper term) then the best place to actually machine is the cylinder Jug/body. The piston to deck gap is quite large on these motors, and well outside the optimal range of a quench gap for real high performance.

The head I used doesn't even have that quench ring bevel in it any more thanks to how shallow it was cut. Not affecting my performance at all.

If any of these engine builders don't ask you for that piston to deck clearance, they aren't worth talking to. Just my 2 cents.

[Biker_Andy]

In removing my casting lines on the TT250 intake I ended up smoothing the sides too much. My understanding is you want the intake rough to keep the gasoline properly atomized. I worry any gains from removing the casting were lost because the sides are now too smooth. Am I overthinking this or is there a way to make it rougher?

[Megadan]

Originally Posted by Biker_Andy

In removing my casting lines on the TT250 intake I ended up smoothing the sides too much. My understanding is you want the intake rough to keep the gasoline properly atomized. I worry any gains from removing the casting were lost because the sides are now too smooth. Am I overthinking this or is there a way to make it rougher?

The finish from 80 grit sand paper is more than adequate to prevent fuel from condensing and pooling on the port surfaces.