Does one really need to put these backing plates on during a conversion. (65 chevelle manual to disc brakes). I see most hot rods do not run them. What problems would I run into if I leave them off my conversion.

Dust,oil,dirt and what ever else is on the road that can get into your front brake system and make it NOT WORK graemlins/sad.gif

I don't have the backing plates for my front conversion so I'm optind so not run them as getting repops up here in canada is expensive!!

I have some buddies that did rear disc swaps on older chevy 4x4's and they run without backing plates just because of the mud, water, etc. My ATV doesn't have them either.

I plan and repacking the bearings once a year at least, so I'm not worried. I asked the same question a while ago: http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=7;t=006198

There is really no need to repack wheel bearings once a year. The dust shields also help direct air into the rotor and wheel bearing area, I would advise using them.