Which of these two springs would be better for a 383 with a custom ground cam with specs that will be close to 239/245...577"/.576" , 112LSA. I understand that both springs require the head to be machined to fit and they both require different seats and retainers, i just want to know which one seems to hold up the best. I'm expecting consistent 6500 RPM use, and i want valve float to be the last thing on my mind. Also, what kind of springs do alot of you 383 guys use and what kind of RPM's do you guys typically see. Thanks guys!

trav

 

I am running the 987 springs and at my installed hieght (1.800) I am good to .600 on paper or about .580 to be safe. Lift in sig. I only rev to 6200rpm and have never had float with this springs with my set up.