[bluegoat65]

I have a set of highports to use on my next project and I noticed there is alot of bronze guide protruding out into the bowl area. I ve heard of porters cutting this excessive amount down to the cast boss of the guide. Being the highports valves are so long would it be safe to take them down (the guides)to a 2" overall length which is what they would dimension out to when cut to the boss.

[steve25]

Unless you where going to port out the heads to there max Int flow I would leave them the lenght that they are for good valve stem support and long ware life.
If you give KRE a call, I am sure Jeff to relay to you when and if by need of flow numbers he would recommend that mod your toying with !

Boat tailing over the least 3/8" of guide can be done to cut down on intrusion area and yet maintain the guides current lenght.

[Elarson]

A shorter guide sacrifices a lot of valve stability and can create vibration modes that will cause the valves to flex and hit each other and/or hit the cylinder walls. Unless you're wanting a potentially expensive and time-consuming science project, I'd leave them alone.

JMHO,
Eric