Thanks for that Alan.
I agree, the overall range of the Miata 6 speed and the Ford T9 5 speed are similar, but with a Miata and 3.54 diff I would have very similar first five gears as the T9 with a long 1st and a 4.55 diff, and the a 6th gear with the same overall gearing as the T9 with a 3.54 diff. This would be ideal for me.
The Motorsport Ireland regulations for Historics (The class I race and hillclimb in ) are very flexible.
(
http://www.motorsportireland.com/Librar ... .sflb.ashx)
Basically, provided the geometry of the engine and suspension is original, and the car is not injected or turboed, modifications are fairly free. The big equalizer is that you are given a handicap calcaluted with regard to the average of your best times in your last 4 events as a ratio of the FTD at those events. The faster your car, the bigger the handicap. A bit like golf ! So there is everything out from 850 Minis to 4.7 Sunbeam Tigers. Great competition on hillclimbs, but you have to watch your mirror on circuits, and it's not such fun for spectators !