I really think it is overkill. You only benefit from a higher spring rate to a point. Then it begins to take away power. Those 135# springs will put much more stress on all the rest of your valvetrain components. (lifters, timing chain, dampner, cam bearings etc.) And with all these haveing high mileage that is an even worse combination.
I really think brand new OEM springs would work best not to mention cheaper & safer.

I think you are right, seeing that even if I were to go to a stiffer spring the lift rate is still the same .550

I just don't want any problems with valve float or rough running due to an issue I could have solved by installing stiffer springs. Then again I don't want any problems with to stiff of springs

thanks for all your help