[Formulajones]

Typical flat tappet spring pressures can range from 110-130 on the seats depending on application.

Honestly I've never worried about it much. If you're running more than that for what ever reason it might be concerning. I've never had a flat tappet that I ran more seat pressure on.

As an example I run a Melling hydraulic flat tappet 068 in the bird and used Johnson lifters on that one, with the crower dual springs. I set those up at 130 on the seat because that's the max pressure allowed in PS racing, what my goal was for the engine. I didn't bother removing the inner spring on break in. I also know the springs will lose a fair amount of seat pressure after they are run a while anyway. I'm probably lucky if they are 115-120 on the seats now. I've gone over 40k miles on that combo driving it regularly and have raced the snot out of it over the last 6 years since the cam install. Still whisper quiet and runs perfectly.