AFR205 Valve Spring Selection - Which Spring Pressure?

The AFR205's wll go be going on my 408W. I have a custom hydraulic roller cam with .581 max lift. Along with my new heads, I ended up with two sets of AFR valve springs. The spring specs are as follows.
- Seat Pressure: 170#, open pressure 445#
- Seat Pressure: 140#, open pressure 378#

I don't want any valve float below 6200+ rpm. I have some concern that the Crane tie bar type hydraulic roller lifters could collapse with the heavier springs. What springs should I use and why?

Even the smaller springs will do with 6200 rpm.Just remember to use minimum amount ( 1/6) turn of lifter preload to minimize valve float. I revved my hydraulic roller lifters to 6500 with AFR 185s 120 lbs springs and 1/6 turn.
[addsig]

I have a set of AFR205s that I was going to have set up by my machine shop for a hydraulic roller and the specs they were going to use were 135# seat and 370# open pressures. Max RPMs the engine would see was 6500. Lift was similar to yours.

450# seems a little high.

I also think the 140# springs would be fine. The guy that designed my custom cam said that he would use the 170# springs. He seems to beleive that a spring under 400# open pressure may have valve float.

Ville: at what RPM did you power start to fall off? Thanks for the input.

I'm running a TFS 24? duration .591 lift hyd roller with 130 seat in my 302. stock holley systemax springs.

what are you cam specs at .02 .05 and advertised?

I'm running a PSI brand spring with my hyd roller that has 0.640" lift. The springs have about 155-160# installed height and about 450# open. I shift mine at about 7100 RPMs and haven't had a valve float problem. But I'm running titanium retainers. Also, I'm running the bigger Cleveland 4v valves, so there is more weight to be tossed around. I would go with the 140# springs.
[addsig]

I will definitely put the 140# springs in. Thanks