Yes, they're about 3/4" taller.
Here's a calculater to get you in the ballpark:
http://www.miata.net/garage/tirecalcold.html
I also have a '64. It's a 4-door V200, 340 bars, stock rear springs, KYB's, normal ride height. I really like the combination.
It's wearing 205-60R15's on 15X7 rims with +13mm offset. Less offset (say, -6mm 15X7 rims) puts the same tires in potential conflict with the lower corner of the front wheel opening, especially when backing out of the driveway.
What are the offsets on the assorted sizes of Rallye's?
235's in the rear might be a problem, looking at wheel tub clearance on the outboard side. Here's a shot from my car with 205's. The fingers are about vertical, with the index knuckle on the sidewall, and the middle finger on the tub.
