I have a 70 Challenger with a 360 six pack crate engine. originally, it was a column shift car (based on my steering column) which was converted to a floor shifting automatic with a 727 tranny. I plan to convert it to a manual transmission but don't know what transmission I should consider. I'm open to any tranny whether a 4, 5 or 6 speed. my only concern is avoiding making big modifications to fit the tranny. I want to avoid cutting the floor if possible. Thoughts?