They seem to be the same diameter, and approximately the same installed height. Try Engnbldr.com in Portland, Oregon for some killer prices on high performance valve springs, retainers, keepers, etc. You can afford to buy a set of their V-8 .600"-lift spring, keeper, and retainer sets, and pitch the extras, the cost is so reasonable. I use them in the roundtrack engines I build, at 6,500 RPM or more, with no problems.

Here's a direct link to their valve spring page. The .550 lift spring is OK for hot street cams, but I prefer the .600 spring for roundtrack racing.

http://engnbldr.com/ChevroletHotLicks.htm

Good people, and really good prices!
Jerry

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