The largest chokes a 45DCOE will take are 42mm (without machining out the body of the carb) and then there is no choke at all.

The works L20B 2000cc engines only just managed 200 hp with 156 ft/lbs torque with all their resources. There is nothing significantly better we can do to the engine today than then.

The basic works rally and race engine specs were 86 x 86mm bore/stroke with Twin 48 webers and 43 mm chokes. They ran both FIA or normal heads with 44mm inlets and 36mm exhaust valves. The valves were 214N stainless that were tuliped and swirl polished with stellite tips then nitrided.

The engines ran cassete style air filters, with an HM53C interference type exhausts with lengthened secondaries.

Most were 10.8:1 on 100 octane avgas or 10.5 on super.

The cam was a wade 479C (76 degree) 304 degree advertised duration.

The cranks had screw in plugs fitted were ground 0.010" on mains and big ends then nitrided and straightened. The rods were the rods were aligned fitted with chev bolts then closed and honed and shot peened.

The whole bottom end including pulleys and clutch pressure plate flywheel were individually zero balanced , assembled the the assembly zero balanced.

They used a Z18T (280ZXT) oil pump.
The sump was baffled and fitted with windage tray.