They all had single valve springs except the 998 Cooper & Cooper S, which had doubles.
997 Cooper's single springs, good for 6500.. were stronger than 850 & 998 Deluxe had.
Single springs were good for maybe 6000 new, less when they get old.
Doubles were good for 6500-7000, but there's not much point, you are well past the power peak with stock cams.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
