68 GT convertible project
This is exactly why wheel/tire fitment needs to be done before paint. Any fender mods can be done now so their aren't any surprises later. I previously test fit a 225/50r18 and it was too tall. It hit the front fender lip and didn't leave much suspension travel. The 225/40 should be ok. As far as the rear, the springs I'm using have a 1/2" longer front segment so the wheels will be pushed back that far already. The 27" diameter should work since the wheel well itself is 30" front to back.
The Dr Diff front brake kit widens the front track by 1/4" per side I think. Then the 73+ spindles increase it even more. It shouldn't make a difference since I'm planning on ordering a wheel with custom back spacing. Finding a wheel "in stock" that would fit though is probably not going to happen.