198 vs. 225 revisited

Hi,
The 198 was made for 5 years.....1970 thru 1974. I have a '74 Duster with this engine but have not driven it enough to do a mileage comparison. Would have to be a same year comparison to be fair. For instance, I bet a '70 model A-body with a 225 could match a heavier '74 A-body with a 198 in MPGs. I think the 170 ran its course and a larger more powerful entry level six was needed with the cars growing bigger and weighed down with more options.