Into the weeds engine design for fuel efficiency discussion.

toolmanmike said

What kind of mileage are we striving for? What year and model of car and what engine should we concentrate on?

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Chrysler big or small block. . Has to be capable of towing when needed. Not interested in hemis, more about lower rpm efficiency. This is specifically about the engine ,but if forced to pick a vehicle lets say a 91 club cab d150. There is no mileage goal per se, just looking for latest tech regarding engine design in terms of efficiency and high compression on crap gas.

For example part 2 I was going to ask what engine would be more efficient in terms of fuel mileage- a small block stroker 4.040 bore 4.0 stroke 6.123 rod and modern heart shape chamber , or a big block 4.18 bore with 3.75 stroke 6.76 rod with bathtub chamber heads? Again same compression, similar cam specs, intake type, etc. How do rod ratio and bore size play into efficiency and octane requirements? Bores and strokes mentioned are just a reference to keep engine cubic inches similar for comparison sake.