any benefit to swapping heads?

Ottmundr said

I was under the impression that with 30* seats, you got better flow at intermediate lifts. If I remember right, I picked that up from watching a lecture by David Vizard.

Are there any flow tests published with identical heads with the only difference in valve seat angle? I always need more education.

Sorry for the thread derail.

Click to expand...

It's not a thread derail. It's about learning. I know DV loves the 30* seat and he and I have hashed it out. He is just dead wrong and I'm not the only one telling him so. Over on speed talk there is a big thread about when to use 50* seats. It's worth the long read.

The very last thing I look at when flowing a head is low lift flow. In fact, total lift isn't even a factor in chosing a seat angle. One of the guys is using a 50* seat on his tow rig and he has less than .500 lift. He says it hauls ***.

Before I bought my flow bench, I heard everyone screaming about shape, shape, shape. And all I can say is that's a FACT and it all starts with the shape of the valve job out in both directions.