I've driven alot of different vehicles.

The worst engine in anything would have to be the Dodge 4.7L that replaced the 5.2 AKA 318. What a piece of junk.

One of the best I'm going to have to say, is the GM Vortec 4200. (Sorry guys.) It's too bad they didn't build a better vehicle around it.

I'm also partial to the Ford 5.0/302. The 88-96 trucks were perhaps the best ford ever made.

 

I've driven, and owned, a vehicle not many left alive have. It was a White, M3A3 halftrack, with the White 160AX motor. Chromoly steel block, and cast iron rings. Not the way motors have been built for a long time. It had a 6 volt starter, big as a gallon pickle jar. Started every time, ran well, even after I sold it. Dependable was its first & last name. I used it, with a bed mounted 800 gal tanker, as a forest fire fighter. It would back up any grade a D-8 cat could climb up. It first ran in 1944, and is still running today, with no rebuild yet. I would not be a bit surprised, if it was running fine at 100 years old.

Baja

 

THE SOHC 427 IS AN ENGINE THAT I KNOW FROM THE 60'S INJECTED ON NITROMETHANE
THEY WOULD TAKE DOWN ANYTHING BLOWN OR NOT. IN THE EARLY 90'S I WAS IN LINCON CITY OREGON AND WHILE READING THE LOCAL NICKLE PAPER I SAW 2 427 SOHC ENGINES FOR SALE FOR $2,500. EA. I NEVER DID ANYTHING ABOUT IT, WISH I HAD.

 

Sorry i just saw this from 7 months ago.
Mine was extremely unreliable.
I bought it brand new.
Took good are of it.
It was always a problem.
From not starting to piston slap so bad the thing sounded like it woukd blow any second.
It was the worst engine by a vast margin I have ever owned....from trucks to boats to motorcycles....just junk.

 

well I owned all the engines that I am going to discuss best ford 300 last well over 300,000 , with little to none break downs,then 302 ,gmc v6,and for no power but complete truck last long old international pickups,worst and I mean worst chevy 80s diesel garbage,

 

my neighbor has a early 2000's GMC 2500 with a 6.0 in it.. thing knocks as loud as my 86 6.9L diesel...

 

I'm kind of a engine guy, and I've worked on many engine so I'll throw out a few the come to mind.
Junk- any Chrysler that ends in 7, 2.7, 3.7, 4.7
Junk- Cadillac Northstar,
Junk- GM 5.7 6.2 6.5 diesels
Junk Ford 2.0 split-port
Junk Olds Quad 4
Junk Ford 351M 400

Some of the good ones,
7.3 Powerstroke
5.9 Cummins
1.9 VW ALH diesel
Ford 4.6 modular in 2v and 4v
GM LS engines
Chrysler 225 318 340 360 383 426 440
GM 3800 V6
6.9 and 7.3 IDI didn't make must power but runs forever
Olds 350 403 455
Ford 300 351W 351C 429CJ 427 428CJ 460
GM 6.6 DuraMax

There is plenty more you could add to both lists, but I've work on everyone one of these listed, now there is also a lot of junk transmissions and good transmissions

 

351m/400 engines powered how many millions of trucks and cars? I dont know. I do know although they arent known as performance engines they were about as dependable as you could get at the time. And there are still trucks running around today with the same engines that have never been rebuilt. And my old Bronco has more than 400,000 miles on it with only 1 rebuild. Junk? I dont think so.

 

Biggest problem I ever ran into with the 351M/400 was oil drainback, the hole on the right rear must have had 3 corners in it, also the left front, but it didn't cause a problem. They were just gutless gas hogs.

 

only in stock EPA mandate form.
remove the restrictive exhaust, 2 barrel intake with egr crap, and smog pump crap.
replace with a 4 barrel non egr intake and 650 CFM carb, 3 inch muffler and pipes, and you will have a very good running engine that will get 15-18 mpg running around town in a 4X4 truck with a C-6 trans.

 

My dad had an old pickup with a 351.
Still has his old Mustang with a 351 under the hood.
Not sure which versions of the 351, but they have been very reliable.

 

If only it were true...

 

In a 2wd truck with 2.75 gears on the highway maybe.... No way in a 4wd in town.

 

i have no problem getting 15-18 mpg with my truck because i do not drive it like a drag racer. when in town driving i am easy on the gas. this is how i get good mileage with it over the course of a full tank of gas.

if i drive it like a 17 year old it only gets 9 mpg.

 

If it's true, you're very lucky. I have a very hard time believing it myself.