[rsk289]

As ever, Dan has it all in his post - the little I can contribute is that the dynamo used for UK-market 289s was a Lucas C40T, the 'T' standing for 'with tachometer drive'. Hawk Cars can provide the correct mounting bracket for this dynamo. I don't know if C40Ts are available without a core unit - they might well be - but Wosp (AES) do sell a 'Dynator' version, which is an alternator within an (aluminium, not iron) casing (you lose the engraved detail on the original style of casing). This can be used with ammeter and all original wiring in conjunction with Dynalite's dummy Lucas RB360 control box, there is just one small wiring change that is difficult to spot (Dynalite change the internals of the RB360 to suit, which incorporates a 'whole system' 50A fuse concealed within). NB - I am talking about the Lucas wiring found in UK cars, not the Ford wiring found in CSX cars. It's also worth noting that whilst US market cars may have changed to Ford wiring in '62-3, COB6029 (Haynes Museum, late '64 car) has the Lucas dynamo setup, so I'd say UK cars stuck with the cable tachometer.
As Dan says, cars fitted with the C40T dynamo had cast aluminium pulleys peculiar to Cobra applications. There appear to be two types: a large diameter pulley for street use, and an even larger one for competition use, presumably to reduce power consumption at high revs. Hawk have had a few of both types made.
Cars with the dynamo also used a reduction gearbox screwed to the output connection. This was identical to the Frogeye Sprite unit, now reproduced and readily available from AH suppliers (but I had to turn down an internal bushing on mine as the clearance to a circlip was incorrect, producing a screeching sound until modified - easy enough, but annoying to have to do it). A Healey tacho cable (although LHD for a RHD Cobra) works fine.
The tacho itself is tricky. There are no reproduction tachos and speedos currently manufactured that are even close for a 289 leafspring Cobra (not 100% sure about coilers, but likely to be the same), all being electronic, wrong face design, wrong pointer, no high beam light etc. etc. The best option I have found for a cable drive tacho with a high beam red lens is from a Sunbeam Rapier, with face reprinted by either Speedycables or Speedograph Richfield etc. to the correct design, part numbers, ratio number etc. If you find one of these, convert it and fit it, you will have to find the speedometer to match also. The shape of the dial face and the design of pointer are completely different from the repro instruments which, as noted above, are not correct.

I hope that adds a little to Dan's information,
Roger