Inliners International Forums General Discussion Engines GMC Straight Six Head Questions

"Most full race cylinder heads don't use angle cutters for seats any more, so the days of the angled valve seats are almost a thing of the past".

what does that mean? is there a word missing? are you meaning they dont use 30 degree angled seats any more? I know, but other than having to stock/use different degree cutters, or stones, or whatever they use to grind, cut, or place valve seats into heads these days, why not get the most bang for your valve job buck?

Now a talking point for a 45 degree seat is the "self-cleaning" ability to better cut thru any foreign surface that may try to adhere to the seat surface and not let the valve completely seat-thus "burning" the seat and valve sealing surfaces.

If you can improve the total flow past the valve, with a seating surface thats a little different than current cost cutting thinking, why not entertain that idea--it aint like a 37.5 degree angle or a 63.7...30s were used in all 216,235 and 261 Chevys and virtually all Pontiac V8 engines for many, many years prior to the "bean counters" rise to power in the industry.

The more total flow idea means if you have a better flowing seat angle thats "gooder flowing" up to .500" lift, and you have a cam with .512" lift. Then you will have more total flow into that cylinder with the "under .500" lift seat angle because you are only in the "bad" flowing lift area (.500 to .512 )for a very brief part of the cycle. It would behoove you to go with the 30 degree seat--Not so if you have a .750" lift cam. "just sayin'"