offset valve seat flow numbers

[sbcharlie]

i used a 2006 harley twin cam cylinder head for the test. the intake seat was offset .030 at 3 o-clock position

intake stock offset
.100 60 62
.200 124 130
.300 175 178
.400 209 215
.500 214 230
.600 213 234

throat ratio 89% stock parts no port work just a mild blend
thanks sbc

[Powertrip]

Interesting results, the problem is I am not sure where 12 o'clock is, therefore where you offset the seat. Pictures would definitely help here. I have seen seats offset toward the short turn, though I've never experimented with that myself.

[mag2555]

It's a canted valve wedge head so my thinking would be that your small rework improved the port bias since your seing flow gains in all lift ranges.

These Heads as you have seen have a large stock Throat percentage so not do any rework to increase that as they do not need it , especially on the Exh side!

If your going for a full rebuild the best thing you can do to these Heads is you install over size valves ( at least on the Exh side ) and then apply a valve job to increase low lift flow and hence velocity, as these Heads to me have too much unused port area for what they flow!
This will also help with the dreaded having to blip the throttle syndrome at idle condition that so many have in trying to the the motor from loading up!