I bought a fps cam locally for my turbo 331 and was looking to see who makes it for them or do they grind there own? Basically i need valve springs and fps told me i need atleast 250 on the seat and 750-800 open. That seems alittle high to me. The specs are .681int .644exh and 264int and 257exh @ .50 (solid roller) The motor is a victor jr headed 9to1 331 with a mp gt45 that will see no more than 20 psi. Or do any of you guys know how to figure out the requirements for valve spring pressures?