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I purchased compcam kit k35-510-8 which comes with cam, springs, retainers, locks, lifters and timing set. I have a set of GT40 heads that I had completely reworked about 4 years ago in anticipation of installing them one day, which is here now. I'll be replacing the stamped rockers with Scorpion 1.6 rollers. Also will be replacing the existing springs with the Comp springs. After removing the springs I measured installed spring height with a valve spring height micrometer with no shims in place. As seen in the pics the range is from 1.755" to 1.775". I've mostly heard that 1.8" is the target installed height on GT40 heads. I spoke with Comp before I took measurements and asked what the height should be and I was told they recommend 1.750" with this kit. (I left the "1" out of the measurements)
Can anybody tell me what the maximum allowable difference in installed valve spring height is? Is the difference in my situation enough to warrant machining the heads or possibly using different length pushrods where needed? As for as shimming goes 1.760 looks seems to be a good target but that would require .010 shims for the five 1.770 spots and .015 is the thinnest I can find. A little help please.
If you don’t get a response here you might want to ask this over on the Small Block forum. There are some guys there that can probably answer you that don’t frequent this 87-96 forum.
Correction on Comps recommendation. It's actually 1.750". They said my high to low is within range, but in an effort to make them closer to each other and the 1.750 target, I'm going to use .015 shims on the 1.775's and 1.770's to yield 1.760 and 1.755 on those eight and leave the others alone. Would really like some feedback.
If you don’t get a response here you might want to ask this over on the Small Block forum. There are some guys there that can probably answer you that don’t frequent this 87-96 forum.
