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400whp sanity check and questions.

No they are not a bad head. I just wouldnt port the intake side. Maybe go little larger valve size. As someone said, unshroud the valves too. Alot people desire the 531 heads, they are still good head, just go about it different than you would with a 530 head.
 
fastcomet said:
No they are not a bad head. I just wouldnt port the intake side. Maybe go little larger valve size. As someone said, unshroud the valves too. Alot people desire the 531 heads, they are still good head, just go about it different than you would with a 530 head.
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My understanding is that stock to stock, the 531 is the best.

Light mods on both, still 531. But when it comes to seeking big improvements, the 530 is actually more desirable.
 
doucheNozzle said:
My understanding is that stock to stock, the 531 is the best.

Light mods on both, still 531. But when it comes to seeking big improvements, the 530 is actually more desirable.
Click to expand...
I think it may depend on how the heads are prepared too. I had an “all out” RSI 530 with extra work done and 48/40 valves and it’s much stronger with the 531 Erland did for me with 46/38 valves (ran the same cam in both). I think Tate picked up almost 100hp doing the same change. I also think Erland is a much better head builder than RSI was, the way he shapes the combustion chamber is really effective
 
If you want more than 210-220cfm the 531 is the better choice. This is the practical limit for the 530 head. (Ofcourse excluding epoxy, welding etc.)
 
Stiggy Pop said:
I think it may depend on how the heads are prepared too. I had an “all out” RSI 530 with extra work done and 48/40 valves and it’s much stronger with the 531 Erland did for me with 46/38 valves (ran the same cam in both). I think Tate picked up almost 100hp doing the same change. I also think Erland is a much better head builder than RSI was, the way he shapes the combustion chamber is really effective
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I have a CNC ported 530 RSI head that was set up for 48/40 valves. The intake port is smaller than what I do on a stock valve 530 port. I can see how it wasn’t a great performer for you and Tate.
 
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