67 Ambassador Convertable rims and tires

I believe the 1967 Ambassadors and Marlins (same front-end parts) had a 0.25" spacer between the wheel and rotor when new. Mine does not. With the 3.75 BS wheels, things are pretty close, but never in danger of hitting anything. There is about 3/8" of clearance from the tie rod and maybe that much up top near the spring mount. These are 14x6 1970s AMC Rally wheels, with 3.75 BS like the original 14x5.5 wheels. So, this'll give you the idea of how far you'd be, without a spacer, with 3.75 BS. Assuming that your setup sits like mine does. Also, there's a little tire bulge even with little 215/70 tires on the 14x6 rims; the bulge goes out about 3/4" out from the rim edge. These tires are 25.85" tall. Original tire height was between 26.8" and 27.4" for the 343 car. The speedo gearing was the same for either the 775-14 or 824-14 tires, so assuming 27.1" tall tires would zero the speedo. There are some real wizards like George on here who could probably tell you within three decimal points what it actually was!

On the back I've got 15x7 AMC Rally wheels. Those have 4.50" BS. So, they're 3/4" further in (closer to the parts) because OE was 3.75. I have enough room for 245/60 tires mounted on them and that's with mandrel bent 2.25" exhaust tubing. But, it's close and I wouldn't try 255/60. These tires are 26.57" tall.

I think if you had 3.50" BS up front (assuming you have the same geometry as me) and 4.25" on the rear, you should be set. You could probably go as wide as 8" on the back, don't know if 10s would hit your wheel arch lip like I think they would on my Marlin.