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

[tonyp25]

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.

 

[YY1]

Every 318 I have ever owned has been super reliable.

 

[73charger340]

If comparing leaks the new stuff is much better

 

[rickseeman]

I think they were reliable but the motors (all brands) sure didn't last like they do today.

 

[sam dupont]

I read a Chrysler statement decades ago that the 318 was their best warranty motor. Much of that is people who bought 318's didn't buy them to thrash.

 

[fullmetaljacket]

I think they were reliable but the motors (all brands) sure didn't last like they do today.

Nothing can surpass the reliability of the famous in-line straight 6ix cylinder. The 318's right there as well.

 

[68BabyBlue]

I drove a 440 GTX as a daily driver in the 70s, a '62 Imperial with a 413 in the 90s, and a '66 Imperial with a 440 later in the decade. Nearly 200,000 miles combined, and no issues with any of them. I'll never forget a business trip one week in January, arriving back at Chicago's O'hare airport in single digit weather after the '66 Imperial had been sitting for nearly a week in the long term parking lot. The look on my colleagues' faces when the 440 fired on the second crank was priceless.

 

[Photon440]

Nothing can surpass the reliability of the famous in-line straight 6ix cylinder. The 318's right there as well.

They reliably cracked exhaust manifolds all the time. Didn't have the power to hurt anything inside the block.

 

[Ron H]

I read a Chrysler statement decades ago that the 318 was their best warranty motor. Much of that is people who bought 318's didn't buy them to thrash.

As a geezer, always heard how reliable the 318/727 were durable, hard to kill, and knew a couple people who beat the living snot out of them. Though back then the 318 was considered as boat-anchor material for anyone upgrading.

 

[Demonic]

All the Mopars I’ve owned have been reliable. That all get regular maintenance too. 318, 340’s and 383’s. I had a 79 W150 with a swapped in 440 that was my daily in the early 90’s, no issues ever.

 

[toolmanmike]

High nickel content in the blocks made them outlast the cars themselves. At 100,000 miles they needed new bearings and a timing chain and gears but everything else was good. (well,the block and bores anyway) LOL

 

[YY1]

I've actually had better luck with 904's than 727's.

I've lost two big block 727's and and one small block, but never lost a 904.

 

[bobsgtx]

To me it depends on what you think reliability is. They took a lot more maintenance like ignition and oil changes. 100k to 150k miles was about it until rebuild unless the body was turning into iron oxide. I always wondered why new engines seem to last longer. Is it better oil, metal use, fuel control or all three? Maybe the big three finally could bore a round straight hole.

 

[oldbee]

I drove a 440 GTX as a daily driver in the 70s, a '62 Imperial with a 413 in the 90s, and a '66 Imperial with a 440 later in the decade. Nearly 200,000 miles combined, and no issues with any of them. I'll never forget a business trip one week in January, arriving back at Chicago's O'hare airport in single digit weather after the '66 Imperial had been sitting for nearly a week in the long term parking lot. The look on my colleagues' faces when the 440 fired on the second crank was priceless.
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Lol, way better gas back then. Stuff now(?) would’ve gone from the fuel bowls in a week.

 

[68BabyBlue]

Lol, way better gas back then. Stuff now(?) would’ve gone from the fuel bowls in a week.

Ain't that the truth! If I spend a day at a car show these days, I can count on having to prime the carb on the GTX, unless I'm running ethanol free.

 

[Fran Blacker]

Didn't 340s running stock class pop head gaskets.

 

[PurpleBeeper]

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.

318 and 225 slant six will outlive cockroaches after a nuclear war

 

[68BabyBlue]

High nickel content in the blocks made them outlast the cars themselves. At 100,000 miles they needed new bearings and a timing chain and gears but everything else was good. (well,the block and bores anyway) LOL

Bodies gave out well before the engines in the slant sixes my dad ran, one that I inherited, and the last Valiant I ran as a daily driver. If the sheet metal had been galvanized, I'd still be driving the '75 Valiant today. Wife made me sell it after I patched the quarter panels, and painted them primer gray to pass PA state inspection in '87, slant six still ran fine with 95,000. I have a buddy who ran slant sixes because his dad wouldn't let him have a big block Mopar. He got those things revving over 7000 rpms with hyper pack induction and cam, and put more than a few rods through the block, but he never broke a crank.

 

[dadsbee]

In 1978 our '69 Fury II had 157,000 miles on it. I put a brick on the gas pedal trying to blow up the 318. No joy! Took the water out of the rad, it would die and just restart after cooling off, was about the take the oil out and Dad came around the corner and stated "just pull the f'n motor already and put in that 440/4 speed you have sitting on the garage floor, I can't hear the customers in the butcher shop" !

 

[AR67GTX]

My used 383/Tflite 64 Sport Fury I bought in 1968 at the not so tender age of 17, survived all the abuse I could throw at it, and it was a fair amount. I sold it in 1972 after I had swapped a cam into it a couple years earlier and the oil pressure at idle was getting a little erratic. Someone told me at the time that sometimes the cam bearings would wear after a cam swap and play havoc with low rpm oil pressure. Not sure if that was valid or the issue but I passed it on. But it still survived a lot of hard running up to then.