predator. valve seat pressure

[DBR1990]

I am putting together a mild build for a spare using an HF Predator. The valve train is as follows:
Mod 2 cam, billet lifters, CM pushrods, 1.3:1 rockers, stainless valves, 26# springs, aluminium retainers w/ split keepers.
my question is, when I measure valve stack height, I measure seat pressure @ 17#.
Can you experts tell me if this is adequate? Do I need shims t get to 26#?
I will rev the crud out of this thing on an 1/8 mile dirt oval.
I am a Harley guy so any help would be appreciated.
Thanks

 

[ole4]

How are you measuring the seat pressure? What is your installed height of the 26 lb springs?

 

[DBR1990]

Installed height is the issue . I measured mine at .865". My understanding is that it should be arouund .815". This is for clones in general i guess. I use a Rimac spring tester for determining seat pressure at installed height. I am using stainless valves with split keepers and the aluminum retainers that everyone sells. I cut seats, and sunk valve a little but not .050". I shimmed springs to get 22# seat pressure, and that resulted in just under 70# at full lift. Is this ok?

 

[ole4]

I am not familiar with the mod2 but that would be OK for the Isky black mamba. Isky also gave a option for Subaru valve locks which lowered the retainer some. I tried them but my installed height was around ,780 with them and I was afraid I would get too close to coil bind with the 1.3 rockers. I usually just make a shim out of aluminum on the lathe to get my installed height.