318 MAX fuel economy builds?

toolmanmike said
Probably get 20+ out of one of those. Most of those had a roller cam, the #302 heads, and a lock up 904 transmission with a low rear gear (like 2.87 or whatever) Heck, my 70 318 2 barrel with a standard 904 and a 3.23 gear gets a steady 19 on the highway.

Lots of the M bodies have a 2.20 gear rear end.

Dan the man said
What's a good dual plane intake?

In this instance I would use the one I had on hand, including an oem one.

To go all out for mileage if I were buying one I would use the SP2P with a small thermoquad.

If I were building a low buck motor from scratch I would use a magnum crank, rods, pistons and zero deck the block. Would use magnum heads, long tube headers, and factory 318 magnum cam.

Even the low compression 2bbl smogged out 318's that came factory in the M bodies would knock down 20mpg plus with no problem. If the engine was good I would just change the timing chain out, tune it up, and run it as is with the 2bbl.