Need advise on Sub frame connectors

I've been checking this site out for yrs trying to find ideas. I'm finally starting to get my 72 dodge dart custom back on the road. I'm currently gathering parts to install a 5.7 hemi into it, it's gunna be relatively stock power wise,. Anyway what im getting at is do I need subframe connectors? And has anyone ever done or seen them on a 4 door?