Why the /6

I had a 170, 4 speed in my 64 Barracuda for a while. It was nice. MP cam, heads milled .060, bowls cleaned up, chambers cc'd, windage tray, 2 barrel and intake, 2 1/4 exhaust with a turbo muffler. Pulled well and wound up tight. Did not sound like a sewing machine. 30 mpg on the highway, cruising. Wish I had kept it now. Slant six is fine by me.