Valve Spring Help (not 460 related)

Hey guys, i'm working on a project and need some advice. I have an International DT408(a destroked DT466 variation) from a school bus. It has a bosch P-pump on it and i'm wanting to change the governor springs on it to raise the governed speed from the stock 2800 to about 3800. The problem is the "internet consensus" is that the stock valve springs will allow the valves to float at about 3400 rpms. What info would I need to order a custom set of valve springs to handle the extra 1000 rpms? I have a factory service manual with factory valve spring specs but i have no idea where to go from there. It does have hydraulic roller lifters if that would help.

If anyone could offer some input i would be greatly appreciate it. I realize this isn't a diesel site but I know most of you are very knowledgeable with a lot more than the big fords!

Thanks,
Dave S.

I take a guess, for you, but it is just that. I would start with the factory manual spec.s, I.d, O.d, installed height, open pressure, and closed pressure, and look for a spring that matchs the dimensions and has about 50 pounds more closed pressure. You might call Comp Cams tech line with the stock spec's and see if thet can help.

Thanks, thats what i was thinking about doing, just getting a spring with a little more pressure and see what happens. I'm hoping that 50-75 more shouldn't be too rough on a hydraulic roller cam/lifter setup because the factory spec open spring pressure is 207-217 lbs. Heck the closed pressure spec is 75-83 lbs.

Dave S.