198 vs. 225 revisited

Less intake valve lift gives more vortices and better fuel-air mixing. Less lift also generally goes along with less intake-exhaust overlap, which is also good.

I referred to the Jeep 4.0L engine as a similar-sized straight six as the Mopar 225 (3.7L), but one that has been modernized to EFI and better spark control. I meant what a 4.0L might deliver in an early-A car (some FABO have considered). You will never get good mileage in a Jeep since the tires alone must take 5 mpg to generate that loud whine. My point is that you don't need to change the whole engine, just the engine controls (intake, ignition). I got 22 mpg regularly in my 1969 slant w/ 1 barrel carb. It is known to have bad fuel distribution (richer in center cylinders). I expect that with modern controls and a lighter early A car, one could realize 30 mpg. Of course it depends on how smart your drive. I get >30 mpg on the interstate in my 3.8L 4500 lb Chrysler minivan by following behind semis at 60 mph.