Will a 66 b-body 8 3/4 fit without cutting?

I believe the '66 is only about an inch wider. Some say you have to move the perches but I've heard of people just bolting them in with no problems. You can pull the spring out that much by hand. I'd try bolting it in before I started cutting the perches off. Your Demon rear is narrrower than the front track so the wider rear will fill out the wheelwells a little. I'm saving a rear out of a '67 Belvedere in case I ever need an 8 3/4 for one of my a-bodys.
Dallas
missourimopar.com