0.5mm oversized valves and ported head vs Stock

[olsonjus]

For you guys worried about making power with this old 4 valve per cylinder head, check out the difference between what a stock head flows and one that has been reworked and has 0.5mm oversized supertech valves on the intake and exhaust:

"i just got my head back from my machinist.
basically did the same exact port work as my last race head but this time i added Supertech oversized valves.
i'm sure everyone here knows what a stock 16v head flows but i'll put up the#s anyways. ps....no side jobs. theres plenty of people on Vortex who can port heads.
oem
intake
.050 26.40
.100 60.20
.105 90.60
.200 128.30
.250 149.00
.300 165.30
.350 170.10
.400 176.80
exhaust
.050 21.80
.100 55.10
.150 93.20
.200 113.80
.250 117.70
.300 123.50
.350 127.80
.400 130.10
big valve
intake
.050 41.80
.100 92.30
.150 128.30
.200 163.50
.250 196.10
.300 215.60
.350 229.50
.400 240.40
exhaust
.050 33.60
.100 72.40
.150 121.80
.200 146.00
.250 165.70
.300 180.10
.350 188.20
.400 191.30
"

http://forums.vwvortex.com/zerothread?id=2358647

[Jamo]

Nice info bit confusing though, my eyes!

[gnutz2]

Good job on your race head, are the oversize valves backcut and undercut, do you have any specs and did you get the valve seats re worked eg, 3 angle or radius?

[Rusty]

Those are some good gains, shame that porting and polishing is so much money.