Re: 1969 Front Tire Size
Not sure how you came up with 3/4 inch difference. The 215 65 15 is 26 inches tall. The 225 60 15 is 25.62 inches tall. Difference is .38 inch. The difference from the middle of the spindle to the ground is only half that or .19 inch, so less than a 1/4 inch difference in ride height in the front. I think it would sit real sweet with that combo.
Here is how to figure tire height.
section width x aspect ratio (expressed as .60 for a 60 series, .70 for a 70 series) x 2
divide by 25.4
add that number to your wheel diameter and it gives you the overall diameter for the tire.
Mind you, this assumes the manufacturer is dead on with their specs. They usually are not. A 235 tire might be 233.5 mm wide, but will be rounded up to the nearest "5".
215 x .65 x 2 = 279.5
divide by 25.4 = 11.0039370078 (I rounded to 11 for your tire height).
add 11 and 15 = 26
Run the same calculation for the 225 60 and you will get 10.6299212598 (actually closer to 10.63, but just to be safe, I rounded down to 10.62 which gives an overall diameter of 25.62
If you don't want to round, the difference in the two is .374015748, with the corresponding difference in ride height .187007874. Still less than two tenths of an inch.
hope that helps.
BTW, you guys have some sweet looking blue Camaros.