Picture of 340/360 head porting....Mistakes?
Always wanted to try 50 or 55 degree seats in those particular heads. As for the chamber being a power loser, I'd love to do some A-B testing on the dyno to verify that. I milled those heads .110 to achieve that form, the chambers measure 54cc so keeping that test apples to apples would be difficult to say the least.
You can fix them...but I won't post how. Cost me many hours.
What you will see with it on the dyno is peak isn't down, but under the curve is down a bunch. It makes the gear change a problem, especially with a clutch. I can't remember if the W-7 was the same chamber as the 5 but I think it was updated.
In th mid 90's, I was talking a lot to Kent Ritter. Fortunately, I took notes (not like CF...he has a sickness with notes in a good way) so I had an idea what to look at. At the time, IIRC, Ritter-Webber was the A/A automatic record holder with a 7.77 at 177. Can't remember the heads but think they started out as 7's.
The best chambers I have seen have steep convex walls. Helps shape the flow into the cylinder. And helps with exit losses. The smart dudes call it Pressure Recovery. Also, it helps with reversion. So do steeper seat angles, but I can't say I totally understand why. I have seen, but never had any 58* cutters. Have heard some talk of 60* cutters, and a pretty sharp dude in Texas hinted to me a year or so ago guys were working with 62* seats. We are talking about ports that have flow curves going straight up at 1.3 inch lift, cam lobes that are essentially square and valve train components as rigid as you can get.
Hopefully, some of that tech will trickle down. Coincidentally, I saw my first 55* seat in 1999 by accident. If it weren't for the extra cost in valve weight, I think you'd see many more people using steeper seat angles, as they are better with tulip valves. Big, long tulip valves need to be Ti.
