I would get the electric kick down switch. Can't it eventually lead to burned clutches? I loved the Olds 307, then Olds 350 in my 78 1/2 ton. With 2.76 gears, even the 307 was a big improvement over stock sbc 350's. Paint that dam motor, either gold or this colour. I used Rustoleum Aged Copper to look like Olds 400.

 

Correct on the no kickdown, but the modulator still needs a vacuum source.

 

Unless you want to manually downshift all the time, I would hook up the kick down, it does not burn up clutches.