Does a higher HP diesel engine have a better mpg ratio

[Barlow46]

Originally Posted by distaff

Worth noting that the 390 was an FE engine, the design of this family began in 1957, and it had a peculiar design were the push rods essentially pass through the intake manifold. The 460 is of the 385 family of engines designed in the late 60's with better breathing characteristics. Of the FE family only the 427 Single Overhead Cam (SOHC) didn't have that problem because the Ford engineers eliminated the push rods with an overhead cam design.

Really hard to make a generalization about fuel economy and power when comparing to such different architectures.

Also, I had a 1973 F250 camper special with the 390 but I had the 4:10 rear axle. I believe you could get the 3:73 with the 427. That alone could account for the mileage difference.

[dennis45]

Originally Posted by Mr_D

Nope, mine was also accurate.

Sorry,,, AND MrD!!

[distaff]

Originally Posted by blackf3504dr

I think you meant to say the push rods run through the intake runners....

You are right, I did. I have a '66 or '67 410 in my '69 F100 4WD. The push rod placement prevents a more efficient cylinder head design, having said that, you can still get plenty out of these old V8s.

It is worth noting that in the FE the intake manifold actually overlaps the top of the block, so the intake runners are partly in the manifold. Only engine I know of that had this characteristic.