I got a 68 B-body and can tell you that XV doesn't do Viper motors so you can rule them out. Magnum Force is pretty familiar with the setup but I don't like the fact that the widest wheel you can do is 7 to 7.5. That leaves you with Alterkation's setup and I'm not sure if they can handle a Viper motor. Let me know what you find as my project is in the same boat. The only other route that I know of would be to call Art Morrison. Well you could always go totally custom, but then your talking lots of money.