I do not think it is worth the hassle to install. The hp manifolds don't offer any power gains on the dyno tests I have seen. I also think you may have interference at the steering column.
no real benefits (or minor benefits) of the HP manifolds would be justifiable for anything other than the "WOW!" factor.
I would think that a 73-foot Imperial would be enough of a “WOW” factor!Have an extra set of HP manifolds and will be refreshening my 73’ Imperial. Would anybody know if they will fit? Thanks.