valve spring specs

Building my blown 540,dart block,aluminum RHS heads, 1471 BDS, 11:1 planning to run 20lbs max boost for now don't have exact cam specs but lift will be high .600's to low .700's looking for some spring pressure numbers to use or better yet a recommended spring and part #. Thanks for any info

 

High 200's.
I'll try and grab a p/n

 

I hope you are using a shaft rocker system or at least a good stud girdle....just make sure that you get the correct length rocker bolts/studs into the head...gotta make sure they have deep thread engagement or they tend to break rocker stud bosses....lower spring pressure helps this issue.....but as Noel Manton suggests, higher spring pressure keeps the valve locks and retainers together at high RPM....but the real answer to your question is use the valve spring that the cam manufacturer recommends....I use Comp Cams 26082 springs and love em.....about 390# on the seat @ 2.00" when installed and then the settle at around 375# after a few runs...you can also install em @ 2.050" or 2.100" if ya want a little less seat pressure....325-350# range

 

Talk to the cam builder and get his choice then pass that info to Manley and get a set of there Nextek springs. But there's not point ordering springs until you have a cam in my opinion.

 

i have the comp shaft rockers for the RHS heads. I have the cam but i have seen alot of recommended spring pressures not be enough for blower boost alot of them seem to be geared for blown gas with alot lower pressures.

 

How fast do you plan to spin this?
Stainless or Titanium valves?

 

Stainless valves and 7000-8000 engine rpm max, 12-18% overdrive or what ever it takes to create 15-20 lbs boost

 

what is the application?
I would say at least 350 on the seat

 

blown alcohol door car 2600#'s