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Bill’s correct as essentially a GM Part being Kustom Headers Flint was GM’s Supplier then.
‘72 Kustom Catalogue below includes Part # 1519 as subject Stamping also GM Part# 3977972 as Cross Reference Chart, was there a GM Hi-Performance Part # for the Sidepipes?
Cool too is other than being a SB application, they’re the same as the Kustom system on the Owens/Corning L88!
~ Pete
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