Isky Valve Springs

[ChrisS]

I’m getting ready to assemble a warmed up 1275 and wanted to know what others have experienced with Isky valve springs. I purchased the up rated 260#/inch (VWE-005 / SP-006) springs but when I went to check assembled spring tension they were about 5# less than stock. I compared the uncompressed height of the stock and Isky springs and the Isky springs are shorter. Now I know that for a given lift the higher spring rate springs will give more tension, but should I be concerned with the closed valve spring tension? Is it possible / practical to put a shim under the spring cup to increase the closed valve tension or will this cause the springs to bind (stock rockers)? Am I over analyzing? Thanks.

 

[jollyroger]

Yes you can shim the springs. I think the seated pressure should be bout 70 pounds. Head guy will know how to do this. From my experience they will not bind. I build engines with just under .5" lift with no bind. But you should check anyway. Isky springs have never let me down.