Nick, sounds like the same symptoms as my mates R400 stopping and then running intermittantly. His problem was fuel pump and we sorted it the day before le mans. My Blackbird is carb as you know so not much help but it sounds very fuel pumpy to me. With it being in the tank is it replaceable seperately? I've got a Blackbird Haynes manual so will look at that to see if i can help any.
I've got to have my engine out by the way , for the first time , as my fourth gear is starting to jump out under hard acceleration. I've got Mings Nova to put back in so all should be fine but i'm in a bit of a quandry as to how much refreshing i should do whilst engine out.
Any advice accepted. I've been pleased with the way the engine and box have been but after god knows how mant trackdays and 8000 miles or so i think a refresh is needed.
Cheers Neil