There's 1-2 Cobra replicas here with 1UZ's, right? Haven't seen anyone yet with a GT40 replica, but would really like to hear from someone who's done it.
Here in the US, if someone even thinks of building a GT40 with anything but a SBF, Webers and a ZF, it's heresy, however I think one of the GT40 replica manufacturers in Oz has actually standardised on the 1UZ/UN1 or G50 as their powertrain of choice.
OTOH, the more "faithful" GT40 replicas do seem to hold their value better than the variants. Too bad the others can't be judged on their technical merit, rather than just their fidelity to the original design.