Front Sway Bars

Hey guy's, I need some advice for my 70 Duster. I have a 6cyl. K-Frame. I'm putting a 340 in it with the schumacher motor mount conversion kit.
This car does not have a front sway bar.
1. Did only 8cyl K-Frames have front sway bars??
2. Can I use a factory sway bar from the 8cyl frame on a 6cyl frame???
or do I have to go to aftermarket on the 6cyl frame???
Thanks for the help...
Pete