Hi Tony.
Good to see another Dax. Mines an old girl (2wd) one of the early ones. I use it purely for sprint and hillclimb. Cosworth YB same as yours. I``m running around 300bhp. (It measured 260 at the wheels) with wasted spark ignition. Have you got a T5 Gearbox?

Heres a view off the back of mine at Goodwood last saturday. Best time was 93.67 seconds but If I had kept on the track with this last run it would have been around 89-90 seconds. www.youtube.com/watch?v=lk8NGqkg7Vo

I have resolved my fuel problems now. It was not actually fuel in the end. although the plugs were not wet there was fuel on the piston crowns. We traced it to the dissy shaft/pinion rollpin had sheared and turned slightly so phase sensor was giving wrong signals to the ecu !