66 Barracuda 18" fitment question

Again, depending on how thick those spacers are, I'm not sure you'll fit them in the front. Also, what rear end are you running as that plays a role on what will and won't fit. You can always try them out. If it were me, and I think I could make them work, I'd probably go with a bbp swap front and rear and avoid the spacers. But again, that's costly and can be quite a bit of work.