Does anyone remember what the reliability of the big and small block mopar engines were when they first came out?

[70Dart]

I have been looking at new cars lately and trying to compare engines which made me start thinking how this process went for mopars back in the day. For instance did the 383 have less issues than a 318? Was the 440 more reliable than the 340/360.

Same thing with transmissions? I’d imagine the 727 was preferred but can’t seem to find a lot out about these statistics for the back in the day. I know what I’d prefer now but just wondering if that was the same back then.

 

[70Dart]

I have been looking at new cars lately and trying to compare engines which made me start thinking how this process went for mopars back in the day. For instance did the 383 have less issues than a 318? Was the 440 more reliable than the 340/360.

Same thing with transmissions? I’d imagine the 727 was preferred but can’t seem to find a lot out about these statistics for the back in the day. I know what I’d prefer now but just wondering if that was the same back then.

I lived through those days and did not see a difference except breakage from severe use. My dad’s 1963 Chrysler 300 had a 383 and 727 in it, but lower performance than a Road Roadrunner. It was never a problem for him and both me and my brother drove it. Next in the family was my brothers 440 Magnum in a 1967 GTX. It ran very strong and never broke though the four- speed did on the drag strip one night. Me second car was a 340 four-speed in a 1970 Dart. Again no problems whatsoever. Now here’s the difference. Cars back then were considered worn out by 100k miles. Good news; they had engines capable of a rebuild if the body wasn’t rusted out.

 

[PlymouthMakesIt]

Properly maintained, all of the old Mopar engines are extremely durable. My family has collected mopars since the late 60s, starting with my grandpa who used them on rural mail routes because the drivetrain and brakes stood up so much better than other vehicles, and they were cheap. He had several slant 6 valiants and volares that would last about 300k miles on the mail route before the body rusted away, engine and transmission still running like new. 904s and 727s didn't seem to have much difference behind a slant, unless it had a lockup converter which was unreliable. His main road transportation for 20 years was a 318 in a 1981 R-body gran fury cop car which I still drive to this day, 175k on it and no drivetrain issues, everything is original, even the lockup converter. My dad also owned an R body 1979 new yorker with a 360 that he used as daily transportation for over 10 years, it never gave any trouble until he sold it. Dad's Coronet R/T was his daily driver in the 70s and went 70k with no issues until it sat for 36 years and mice ruined the valves. He had countless new yorkers with 440s that never gave trouble, pulled the engines and built race motors out of them that he still runs today in his 70 cuda. He put one in a dodge truck and pulled his race cars countless miles to races every weekend. I recently dug a C body gran fury police car out of his junkyard that has a 400 with 138k miles now, it runs and drives extremely well after it sat for so long.

If you know how to take care of a car, an old chrysler will last a very long time. Change the oil and filter every 2-3 thousand miles with a good quality zddp oil and reputable filter, run at least midgrade fuel, run a stacked transmission cooler and engine oil cooler, and let the oil get up to temp before driving aggressively or shutting the engine off.

 

[Geoff 2]

In the early 60s, Chrys offered a 50,000 mile/ 5 yr drivetrain warranty. My understanding is that the other companies kicked up a big stink & the warranty was later withdrawn.

 

[YY1]

5/50 went through the early to mid 1990's, then became a 3/36 (just in time for me to buy a 2 year old Dakota)...and then back to 5/50.

 

[AR67GTX]

Compared to rocker arm and valve failures in early Chevy 396/427 engines the B/RB Mopar engines were probably models of reliability and durability. I remember meeting a guy at work during High School in 1968 or early 69 who had a 63 409 Impala. He told me he had put a 427 in it for awhile but it blew up so he stuck the 409 back in it. I thought he was pulling my leg as the 427 had only been out a couple of years and for a high school kid to have bought one over the counter, install it, blown it up, and replaced it with the 409 again, seemed a little hard to believe. But he invited me over to his garage one day and there it set on the floor with a big piece of the lower block casting gone, now just a big boat anchor.

 

[Rebelrouser]

I have been looking at new cars lately and trying to compare engines which made me start thinking how this process went for mopars back in the day. For instance did the 383 have less issues than a 318? Was the 440 more reliable than the 340/360.

Same thing with transmissions? I’d imagine the 727 was preferred but can’t seem to find a lot out about these statistics for the back in the day. I know what I’d prefer now but just wondering if that was the same back then.

My family drove mostly mopars as I was growing up. I remember my Dad buying a 6pack on the way home from a trip because our 67 coronet turned 100,000 miles and the valve covers had never come off. Super reliable car. It was replaced with a 71 Fury 383, and it was super reliable as well. My first Mopar was a 1970 Dart 340 manual 3 speed, it was super reliable as well even with all the street racing, I did.