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What makes a Mopar engine special or different?

Moparfiend

Moparfiend

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So I’m asking this question because I’m wondering what are some of the details of let’s say the Chrysler LA small block that makes it different than a GM small block from the builders perspective.

Can a Chrysler guy build a good GM engine and can a GM guy build a good Chrysler engine? This when considering to have your engine rebuilt should it be by a Chrysler guy? What is a Chrysler guy?

This for example came about when I was going through my heads. I noticed that the rocker arm shafts were not put in correctly. There’s a notch in them that shows correct orientation. I didn’t know this at the time, but I did notice that when I checked for oil flow during priming, the lifters weren’t getting correct or any flow. After investigating, I realized the shafts were reversed, and the oil holes were not lining up. An experienced Chrysler guy would know this right away, but a GM guy might not.

So what other main differences or minor peculiarities are there? Can a GM guy easily build a Chrysler engine if he’s a competent machinist and builder or is there something inherently different about Chrysler engines versus GM engines?
 
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An engine is just a big air pump but all the tricks that work on a Mopar might not work on the others....but basics is basics. I used to buy Mopar race cars that some Chevy guy couldn't make run good so it was basically discarded and gave up on it.
 
Cranky said:
An engine is just a big air pump but all the tricks that work on a Mopar might not work on the others....but basics is basics. I used to buy Mopar race cars that some Chevy guy couldn't make run good so it was basically discarded and gave up on it.
Click to expand...
I guess I’m looking for the details as I stated above as to what makes these blocks and heads that much different. I know on the LA engine lifter angles are much more pronounced, but it’s stuff like that. I’d like to understand better.
I also understand that a Chevy guy may not know the right combination of cam specs, and compression ratio deck, height, and piston, exposure, etc., that an experienced guy would know. And maybe that’s the real extent of this whole question is just getting the right combination??
 
A competent engine builder should be smart enough to know what they don't know and seek out the appropriate information. Over the past 50 years I've built dozens of Ford, GM and Mopar engines and repaired or modified dozens more. I always had reference materials handy for torque specs and engine specific assembly details, like the rocker shaft example cited.

At the end of the day, parts are parts and proper assembly practices and attention to detail remain the same regardless of engine manufacturer. A competent engine builder should be able to work on anything.
 
Rocker shafts are oiled by the head. If the lifters were not getting oil, you have the wrong lifters.
A mopar engine builder would know that. So would a good machinist. But wrong lifters are advertised as fitting, so there is that.
 
Black_Sheep said:
A competent engine builder should be smart enough to know what they don't know and seek out the appropriate information. Over the past 50 years I've built dozens of Ford, GM and Mopar engines and repaired or modified dozens more. I always had reference materials handy for torque specs and engine specific assembly details, like the rocker shaft example cited.

At the end of the day, parts are parts and proper assembly practices and attention to detail remain the same regardless of engine manufacturer. A competent engine builder should be able to work on anything
Click to expand...
My first engine rebuild (overhaul?) was a 289 and with a little bit of cylinder clearance, it ran pretty good for being a small engine but I've been able to make 318's run pretty good too even without extra cylinder clearance. Ran the 289 at the track and it did a 15 flat in a 66 Mudstain FB (3050 weight) and the teen did a 13.51 in a 2950 car. The 89 didn't get the gears and cam that the teen did though.
 
Black_Sheep said:
A competent engine builder should be smart enough to know what they don't know and seek out the appropriate information. Over the past 50 years I've built dozens of Ford, GM and Mopar engines and repaired or modified dozens more. I always had reference materials handy for torque specs and engine specific assembly details, like the rocker shaft example cited.

At the end of the day, parts are parts and proper assembly practices and attention to detail remain the same regardless of engine manufacturer. A competent engine builder should be able to work on anything.
Click to expand...

Thanks those are good inputs. It seems reasonable to me. I was just wondering if there are any peculiarities or differences in the assemblies that a “Mopar” builder would know that other builders wouldn’t.
But what I found interesting is that many assembly techniques are common across manufacturers of this era. It’s almost like they were using each other‘s designs to create theirs.
I’m sure they were doing competitive teardown analysis back then…..
 
I am a machinist and have built: Mopar. Chevy, Ford, Nissan, Toyota, Industrial, Diesel, Rolls Royce, Alpha Romeo, Tractor, Car, Truck, and much more than I can remember. Yes, someone can specialize on one brand, but a machinist that pays attention to the details and can identify whether the parts are correct for the application can do a better job. I have had more than one customer bring in their parts that they just got from Summit Racing that would not fit or were wrong for what he was doing, 'But that is what the SR guy on the phone sold me!', to which I reply "He only knows how to poke buttons, not know which combinations of parts will work for you.
 
Let me put it this way.. I was a VW mechanic in the early-mid 80's, when there where still a bunch of air cooled that hadn't rusted into the ground..

You had 2 types mechanics that maintained them. Those that changed the oil every 3K miles and sucked a exhaust valve when it stretched..

Or the ones that changed the oii and adjusted the mechanical valves every 3K and it lasted twice as long..

Every brand has it's oddities..
 
69Bee said:
I am a machinist and have built: Mopar. Chevy, Ford, Nissan, Toyota, Industrial, Diesel, Rolls Royce, Alpha Romeo, Tractor, Car, Truck, and much more than I can remember. Yes, someone can specialize on one brand, but a machinist that pays attention to the details and can identify whether the parts are correct for the application can do a better job. I have had more than one customer bring in their parts that they just got from Summit Racing that would not fit or were wrong for what he was doing, 'But that is what the SR guy on the phone sold me!', to which I reply "He only knows how to poke buttons, not know which combinations of parts will work for you.
Click to expand...

Unfortunately the day of people saying "this will work" are gone.. Instead of being gearheads themselves, they are anyone they get off the street, or worse, some alley in India. They work out of a "playbook", which tells them what answers to give. "Can I put a Dominator on my 1 bbl slant six intake with an adapter and get good gas mileage"? "Yes, the Dominator is an excellent choice for mild street applications and will work well in your configuration".
 
What makes Mopars better? (At least in the big block area.) Is the rocker shaft design vs ball stud. Wedge, then later hemi, has more room for expanded air flow than GM.) Hemi had 2 rocker shafts that are more production cost, but better design for 2 valve performance options.

Just my opinion.
 
Special? LOOK at how well supported the lifter bores are in a Mopar big block:

383 38.jpg


Now take a look at a Pontiac 400:

1755929273845.png


Mopar valvetrain is superior to other brands. Our lifters are fully supported but hey....maybe the Pontiac has faster oil drainback to the pan???
Pontiacs had 4 bolts around the cylinders like the LA series, making them more prone to head gasket failures. The Mopar big block had 5 bolts per cylinder.
 
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