valve spring question

I have a 461 bbc with a 14-71 blower twisting it 30% over with dart 360 heads , the boost is unknown, heres are question what seat pressure and brand name valve spring do we use because i think the amount of boost is pushing the valves open in upper rpms i used to run it 20 % and didnt have a problem , i think this because its reading a hot egt no matter what pill i put in it.

 

I run around 340 - 360# seat pressure Netex springs... Throw them away when they get below 320#

 

Valve Springs

I pulled the build sheet for our heads and here is the info. Manley Nextek springs #221448 360Lbs closed @ 2.09" 1070Lbs open @ 1.2 .900 Lift. These are also Dart 360 Heads


Corey

 

You can get it so over center on the rich side that the egt's keep going up the fatter you make it. It's because it is still burning fuel as the ex. valve opens and you have fire in the pipe.