RE: Non-hypothetical question, 1098 vs. 1275

As far as fuel economy goes, a stock 1275 can do quite well. I actually checked 
the mileage on my 67 (many years ago). On a long highway trip I found that at 
3500 rpm it got 36 mpg. At 4K, it got 38 mpg... It was a stock thin wall 
pre-smog 1275 with 4 speed and 4:22 gears. I figured that it was in its sweet 
spot at 4K and spinning freely whereas it was laboring at 3500 rpm, thereby 
using more fuel.

YMMV,
Kent
1960 Bugeye
1975 Midget some day auto-x-er