I have a future build coming up, a 49 Dodge pickup. Its just sheetmetal and the original frame, that I'm not real excited to use that original frame. I have an option to use a pretty clean early Dakota 4x4 chassis, or I could build something from parts & pieces (I'm a retired welder).
For the most part, this truck will see very little work, pleasure driving mostly, and most of that will be in town or short highway trips.

Modern Mopar engine choices that can be found locally at reasonable prices are pretty limited. 3.6, 4.7 (which I will not use and are very hard to find good usable around here), or a 5.7. Then it goes back to the 5.9 or the 5.2, or even farther back, which barely falls under the "modern" engines.

I can live with a 100K engine that is in good shape, but 200K is a different story. In our area, the 5.7s are still bringing pretty big money, or have lots of miles on them. The 3.6 are pretty easy to find, and are pretty cheap. The 5.9 and the 5.2 are getting hard to find without huge miles on them. In town driving with any of the V8s get you 10-12 mpg, the 3.6 gets near 20 in town.

To put things in proper perspective, my 48 Plymouth coupe has a 3.9 with a 5 speed and I'm OK with that, the 3.6 actually has a lot more HP then the 3.9. With current gas prices hoovering around $3 a gallon and I don't expect them to go down much (especially since our state just added a 19 cents per gallon sales tax), I don't feel the need to feed, a Hemi to drive around town, and the Hemi power would probably get leadfooted me in trouble, the V6, probably not so much. Gene