4.0l -v- 3.6l engines

[mickrw]

Could one of our more knowledgeable members please let me know what the differences are, apart from size, between the 4.0l and 3.6l engines? I have a new Tuscan which has the 4.0l engine, is this more or less reliable and how much more or less power does it have over the 3.6l engine? Does anyone know why TVR started to use the 3.6l in the standard Tuscan?

Cheers
Mick