It’s been a long project but Cooper S blocks are finally in stock! Proudly made in the UK 
part number 38G466, £3,329.17+VAT:-
https://www.facebook...38238941663347/
In stock
"Mini Spares own Cooper S block based on the thick flange block with same original casting numbers AEG312/AEG634 and design features as used and built by Morris Engines Coventry for the assembly line. With research, design and testing over a 7 year period the block has been modified and improved with historic racing and standard road use in mind. Giving approximately 20% better cooling,with improved water jackets it means the std bore can only be increased to plus 60 oversize but many race series categories only allow plus 20 oversize. Core plugs are supplied but not fitted. Release valve seat is fitted but less cap, valve and spring. Engine is bare and not painted. Fitted with special steel maincaps,studs and bolts it is line bored and blocks are fully blue printed. The camshaft bores are also line bored but cam bearings are not fitted or supplied so customers can choose their own requirements for their camshaft being used. The blocks are currently being used for racing with rave reviews. Sold in std bore size format and require honing for choice of pistons to be used but for reference. 1275 std bore 1275cc is 2.780"-70.6mm. 1275 20 thou oversize 1293cc is 2.801"-71.145mm. 1275 40 thou oversize 1311cc is 2.821"-71.65mm. 1275 60 thou oversize 1330cc is 2.842"-72.16mm. There is also an article under mini stories on our website called "Engine block casting numbers and conrods" showing later blocks where Morris engines were trying to strengthen and improve water jackets and rigidity on the whole block for racing which shows raised ridges between the coreplugs, but in the end solid wall non S block were favoured which had more metal around the cam follower inner wall holes especially, which gave more rigidity all round, making the solid wall block ideal for 8 port head and other high power race cars being produced by Special Tuning and other companies. The S block was stretched from the A30 with 803cc originally to Cooper S with 1275cc and even the S con rods required more metal and strengthenig in certain areas and had to be modified by Morris Engines at Coventry when their research engines showed faults under race condition testing. All blocks are supplied unpainted."
https://www.minispar...-cooper-s-block
Edited by mab01uk, 07 November 2025 - 09:09 AM.
