What are the spring pressures and what is the installed height? There are tons of people using Conical springs from Manley and PSI in road racing and other endurance applications *if* you can keep the spring pressure reasonable. There are conical springs that support in the neightborhood of 250/750psi at .800 lift but any more pressure or lift than that and yo are back to a conventional spring. I try to use dual springs (keeps the weight down) with no damper (eats the Ti retainer) if possible.

THe main problem I have had looking for conical valve spring for a big roller cam is installed height. It seems that the newer engines have tiny rocker boxes (aka LS platform) and the installed height is tiny (like 1.800). From my research most of the new style (conical, beehive, etc.) are geared towars newer engine platforms (G3 Hemi, LS, Coyote).

If you are looking for endurance springs the Isky Tool Room, Manley Nextek, and PSI RML series springs might have something for you.

It has been unanimous across all of the manufacturers I have spoken with that using the lightest valve, spring, retainer, lock and lash cap combo one could get away with *reliably* was preferred. That said they were all in to use a lighter spring until we started talking power adders and then they steered me right back to a 1.550ish OD spring again. In my case we are talking 2.050" installed height and 300/900psi with about .800/.787 net lift. I am going to use the PSI 1254RML dual spring in this case as it is the lightest valve spring I could find that supports the pressures my cam grinder spec'd.