There is nothing special about these A Plus single valve springs.
The valves were a longer fitted length, but fitted the later 998 and all 1275 versions.
They are an excellent replacement for any single spring 1275, Austin America, 1300, etc.
At 1.320" fitted spring length the seat pressure is 70lbs, whereas the AEA311 is only 35lbs.
The AEA311 was fitted to Pre A Plus 850 / 998 / 1100 engines and as an outer on twin spring versions.
Our C-AEA526 valve spring kit will replace all early Cooper or Midget twin spring type A series engines. Free length is 52mm.
Recommend: 8 x 12G1015 per Mini.
For Pre A Plus 850 / 998 / 1100 valve springs, see AEA311