| Bore | 76mm |
| Stroke | 76.7mm |
| Capacity | 348cc |
| Crank shaft | Machined from one piece of EN40B steel and nitrided |
| Connecting rod | Forged steel with plain big end and bushed small end |
| Piston | Forged alloy, 2 rings, cross braced pin bosses, low friction coating |
| Crank cases & covers | Machined in-house from precision magnesium castings |
| Main bearings | Works type flanged double ball race on timing side. 2 x needle rollers on drive size |
| Oil pump | Bronze body, as original works bikes but with F1 style modern porting |
| Cam drive | Bevel driven vertical shaft with splined tube (as 1959 on) |
| Magneto drive | Via toothed belt |
| Barrel | Machined from solid alloy |
| Bore | Nicasil plated |
| Head | Machined in-house from precision L169 alloy casting. Ported by hand |
| Valves | Plasma nitrided stainless steel, lighter than original |
| Valve actuation | As original, direct acting DOHC |
| Valve springs | Double helical springs, fully enclosed in magnesium castings |
| Pushers | Lighter than original with low friction coating |
| Carburettor * | Amal GP |
| Ignition * | PAL magneto |
| * Items marked thus are not included if engine is purchased separately | |
| Please note that Works Racing Motor Cycles Ltd. reserve the right to alter specifications at any time |