Well, so these are never used before W2 long valve heads, MP P4529995. The MP intake valve for these was P5249195, which was a 5.280" long valve. They called out a spring installed height of 1.95-2.02". They are a 3/8" stem valve and mostly no longer available, at least when I was looking for them I could no longer find them. Either way, even if I could get them I wanted to go to a 11/32" stem valve anyways.

So the Manely valves are a tad shorter, that being 2.240", which in turn meant that I most likely could not do a longer spring, short of running some offset locks and/or retainers that allow me to gain some height.

When the heads went to the machine shop I had asked for a 1.900" installed height setup which included the spring locators (0.060" thick). When they measured things out it turned out we were short and the advice I got was NOT to machine the springs seats in the heads given the water passeges beneath. The other option was to re-do the valve seat, sink them a tad to gain on the upper end, but that just seemed like an idea not worthwhile pursuing. It is cheaper to go the route of a new set of shorter installed height springs than it is to machine new seats.

That is basically how I got to where I am today.

I suppose another option would be to do away with the spring locators, after all this is an iron head. However, given the cam I'm running and the .580 lift I wanted to keep the valve centered as much as possible to do away with any guide side-loading (in case of spring walk). Now, that maybe a BS worry, I simply do not have the experience to know any better, however from a theory perspective that made sense.