Point taken. I just happen to have a 73 240 that my son and i are bringing back to life soon, and yes they fit. At least the fronts do the rears will need the same fender rolling as my 280z. The two cars look to be very close dimentionaly. The bigest diference i can tell are the rear strut towers, but that dosn't look like it will be a problem.
I run the snowflakes on my 77 280z. 185/65/15 front 255/60/15 rear. I needed to roll the rear fenders for clearence but that's about it. I use stock suspention, you can see how it looks on youtube under monster 280z. hope this helps.