Alternative SB waterpump

hi guys not really A Body specific but it is Mopar related. Im in the process of building a Dragula style coffin car. Ill be using the only drive train worth using(Mopar of Course). Plans are to use my low mileage 318 from my aspen(>20,000 mi). Im trying to see what my options are as far as waterpump. Being the engine is going inside the coffin it has to be as short as possible. The farther forward I can get my engine the better. What are all my options to choose from?