Viper,don't forget Packard Merlins on Mustangs!

You'd be surprised to see how many warbirds owners and operators tend to go for an accurate engine selection: the third generation of warbirds owners do any possible effort to have their machines to wartime specs,down to wirings,radios and equipment (working gunsights are a must!).

Same goes for superchargers: the era of non working superchargers is gone,pretty much everyone is going for working ones.

It's all down to how deep the pockets are and availability of parts.