I would go with the Gennie Center Mount on your 350. Check out the following links. The Rod Factory can provide you with everything you will need.

The manufacture "Gennie Shifter Products" does not sell retail so you need to pick it up from a speed shop or custom builder. I just purchased one for my 29.

http://www.rodfactory.com/NewFiles/shifters.html
http://www.hotrodhotline.com/gennie/#shifters