The L2399F uses a different oil ring than the 14097021. The 14097021 uses a low tension oil ring. Better off to replace your pistons with the same part number, or a whole set of the L2399F's, or you'll be goofed up when it comes to getting rings. L2399F is a Speed Pro number (used to be TRW), the "Z" in front of the part number is only a Summit Racing thing. I have at least a couple full sets of GM #3999295 (std. bore), which is the part number which is identical to the L2399F. I'm sure I have a rod too... 7/16" bolts in the rod?
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