The front place will have to be countersunk as shown "X" to take the screws CMZ407, which will replace the existing hexagon headed screws, which would foul on the timing chain. Check for clearance on chain all round and align gears as per workshop manual.
When using "A" plus timing covers, there is a small round pressing at the bottom which needs making flat to allow timing chain clearance.
Ensure that the timing chin oil thrower 12A1148 is correctly fitted with the letter "F" facing you, or on early engines, the lip facing outwards.
Duplex Cam Drive - Cam timing information
Minispares duplex kits are genuine AE Hepolite products now owned by Federal Mogul who were the original engine components supplier for Mini. It is however very, very rare that simply fitting these cam drive gears will give the correct cam timing for any particular camshaft installed. Although it will likely to be very close on factory-ground OE camshafts, or from new blanks it is unlikely to be the case on re-profiled camshafts. The main reason for this is when the cam re-profiler needs to make sure the new profile and LCA (lobe centre angle- angle between lobe centres of inlet and exhaust lobes) will fit the core cam being used it may be necessary to re-align the cam lobes in relation to the cam gear key. Because of this it is highly recommended that the cam timing be checked/ re-set to the cam manufacturer or cam suppliers specifications to maximize performance potential.
The method for this depicted in various forms on the Mini Spares website - www.minispares.com - in Articles' sections, 'Calver's Corner', 'Camshafts', including methods where no specialist equipment is on hand.