I am having difficulty understanding what size spring I can use on Sportsman II heads. Right now they have the current 1.25 spings that came on the heads, but my new cam selection says i need to upgrade to the Comp Cams 977 spring, which is 1.460 diameter and 1.850 height. The tech guy at Bill Mitchell says these heads are tapered or something to except up to a 1.550 diameter spring, is this true? How can they come with 1.250 and fit a 1.550 spring with no machining? He also said Worlds 1.437 spring is good to .600 lift and the cam I am going with is a solid roller .575 lift. He said that Worlds spring are narrower and taller and Comps are wider and shorter so i should be fine. Can any body give me any input on this subject. I really want to go with a new cam like the XR280R or the 300AR but cant afford to the machine the heads.

Thanks, Erik

I would use the recommended (by the cam manufacturor) springs over the "generic" springs that the heads come with. The 977-16 spring is made for a roller cam and is quite stout. There is more to it than just being able to handle the lift. I don't doubt that the sprotsman heads will accept a bigger spring. My pro-toplines came with 1.44" springs but the spring pocket will hold up to either a 1.55" or 1.625" diameter spring (I dont remember which). You should be able to measure the spring pocket easily enough.