30 Degree vs. 45 degree on DOVE's

I'm doing up a set of DOVE's for my brothers 501. They currently have the 30 degree intake seat. I have always believed that the 30 degree seat is better at moving air in low lifts situations, but at the cost of some high lift flow. Long story short, we're looking at a street/pulling truck motor that will be expected to make power in the 5000-7000 rpm range. We're looking at a healthy flat tappet mechanical cam. Split pattern, 250/260ish@.050. Lifts in the mid .600's. Should I keep the 30 degree seat or switch it to a 45, or even a 50? We're switching valves anyway, so it wouldn't take much to alter the valve job. Thanks for any advice.

Answers;

1. Switch to a 45* valve job.

2. Use a 30* backcut on the intake about .075-.080" wide.

3. Do not attempt a 50* valve job with those heads. The chamber shape and design is not compatible with a 50* valve job.

Hope this helps,

Charlie Evans

Baitshop wrote:I'm doing up a set of DOVE's for my brothers 501. They currently have the 30 degree intake seat. I have always believed that the 30 degree seat is better at moving air in low lifts situations, but at the cost of some high lift flow. Long story short, we're looking at a street/pulling truck motor that will be expected to make power in the 5000-7000 rpm range. We're looking at a healthy flat tappet mechanical cam. Split pattern, 250/260ish@.050. Lifts in the mid .600's. Should I keep the 30 degree seat or switch it to a 45, or even a 50? We're switching valves anyway, so it wouldn't take much to alter the valve job. Thanks for any advice.

What angle is best will depend upon the valve lift used and which angle gives the best flow curve to take full advantage of THAT valve lift.

Above about .550" valve lift to around .750" valve lift, a 45* seat is usually superior ... at about .450" valve lift or under, the 30* seat is usually superior.