Rolls-Royce–Bentley L-series V8 engine as the "six and a quarter" litre engine. When new, the Rolls-Royce/Bentley V8 was rumoured to be an American engine design licence-built, but it was developed in-house by Rolls-Royce and Bentley engineers. This can be seen in its design characteristics, with features like an aluminium alloy cylinder block with wet liners, gear-driven camshaft, (initially) outboard spark plugs and porting inspired by the Rolls-Royce Merlin aircraft engine. The bore spacing of 4.75" was unlike any American V8 engine and the firing order was 1-5-4-8-6-3-7-2 something uncommon in any period American OHV V8. The deep skirted crankcase design is also rare with
Rolls-Royce Welland Minister of Aircraft Production and the Boards of Rover and Rolls-Royce, the Rover jet factory at Barnoldswick was exchanged for the Rolls-Royce Meteor tank engine factory in Nottingham. A handshake sealed the deal. Rover handed over a total of 32 W.2B/23 engines to Rolls-Royce as well as four "straight-through" W.2B/26 engines, developed by Rover's Adrian Lombard. The W.2B/23 became the RB.23 Welland and the W.2B/26 became the RB.26 Derwent. Adrian Lombard moved with the engines from Rover to Rolls-Royce. Stanley Hooker helped in the task of ironing out the remaining problems, and things soon improved. A flight-quality /23 was fitted