I would like to see the pros and cons of building and swapping a 460 or Cummins. I'll start with some background info on my truck I have a 1978 F-150 4x4 460/NP435/205 it has 4.56 rearend gears on 35" tires. Also with both engines I would install a 5 speed manual whether it be a ZF5 or a NV4500. But here are the two options:

1. Pull the engine out, put new heads, fenderwell headers, Holley efi, and just beef the engine up.
2. I could also get a Cummins 12 valve and put it in, with just straight exhaust and maybe a couple modifications.

I do tow some, I do drive the highways a good bit as well, it's pretty much a DD. Overall factoring everything such as best gas mileage, most power, more reliability, and the pros and cons of both engines. I'd just like to see what others opinions are.

 

Fuel economy is a question mark. The cost of the diesel conversion would eat at fuel cost savings for decades. This is not a fuel economy vehicle anyway.

Reliability: Stay 460. Everything works now, right?

Power: Cummins for torque, 460 for HP.

Gearing: You didn't ask but you might have to regear for the diesel even with the tall tires and OD trans you are planning.

Daily Driver: See reliability.

The Cummins will take almost 3 times the oil as the 460 with oil change intervals the same or no more that double the gas. Filters are much more expensive. And they drool.

Changing to the Cummins is a much more involved rework of the entire powertrain, fuel system, cooling, exhaust and control. Add some frame boxing and maybe suspension work as well.
Hopping up the 460 and going to a ZF is pretty much all just OEM parts changing.

 

I put a lot of thought into this question for my build.

I'm putting in a built 460.

The 12V does get better MPG, but maintenance costs are more. Look into doing an oil change on it verse the 460 for example.

Diesels are used different, a quick start up and going a mile and that's it isn't the best for them, though the 12v is a stout engine.

The 12v will also shake a lot more. You will hear the engine a lot more than the exhaust. In my personal opinion they drone a lot more.

Putting a ZF5 behind a pre-79 460 is... interesting. I'm doing that right now. Pre-79s are internally balanced, Zf5s went behind externally balanced. Basically seem to need a kit for the Zf5 and zero balance it.

A built 460 just sounds beautiful. Personally I prefer a big block sound over 'rolling coal', but to each their own.


At the end of it all if you're not towing A LOT, a 12v is a lot of work and cost. The 460 already fits. But do what makes you the most happy. Either way would be cool.