Nitrous+cheap converter?

However with your lack of detail of what you are doing who knows for sure..

More info, Trans will be a 904. Looking at a 2200-2800 range for the converter. Diff gears are 4.3:1, and tyres are 28" slicks. Engine is a 318 with 675 heads, fitted with 1.88, and 1.6 valves.
Weight of the car, at a guess I'd say somwhere around 1400kgs. (I wont know till it's built, and I can weigh it. lol)