I am curious about those of you who run 150-155lbs (360-365lbs open) of valve seat spring pressure on a hydraulic flat tappet cam. Have you had any issues with hydraulic lifters on a street car with these spring pressures.

I made a rocker arm swap (stock stamped to 1.65) last Winter in my 340 and at that time I had a vendor specify that I needed to use their 120lbs/310lbs springs. So I installed them and drove the car this year and I noticed that the engine would not run any higher than 5600rpms after this rocker swap. (let me clarify. If would, but the power died off quickly past this rpm. Before the swap it would rev cleanly to 57/5800rpms with smaller springs and 1.5 stock rockers.) I discussed this with two different Mopar engine builders, and two different spring manufacturers and they all told me that I needed more spring pressure due to the 1.65 rocker ratio and 2.02" valves. They all suggested an average of 150-156lbs on the seat and 350-375lbs open.

(Note: my original cam card showed 135/300 with 1.5 rockers. But I was not asked and I did not even think about checking what the cam card suggested "at the time" that these springs were specified).

I just finished with my spring swap and all the installed heights came out to show 153lbs average (1.810"-1.824" IH) on the seat and 361/362lbs average open pressure (per the spring chart) at .540" lift. I plan on keeping the WOT shift points at about 5800-6k rpms.

I may not get a chance to drive the car again this year due to the weather, but I just wanted to make sure that there is nothing else that I should be looking at before Spring.

Notes: My cam designer (S.B) said that the cam core will handle these spring pressure with no problems. Comp says that my hydraulic lifters (High Energy) max out at apx. 360lbs but they should be fine. My rocker arms are Yella Terra 1.65's that are rated for 600lbs. My push rods are Manton Series 5 (5/16" x .118" wall, 275,000psi), and I use Brad Penn Green Oil.

I know that I am right on the edge with this current setup, but can I stick with the existing Comp High Energy lifters or should I try a set of the variable timing lifters with this new spring setup?

Thanks