75 Duster vs 71-72

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burrpenick

'69 Barracuda
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I know they had lower compression, altered cams/timing etc, along w/large pattern wheels and front Discs. But other than the HEAVY BUMPERS, what else is actually different?
 
grills and tailights ? Inside door handle location?? Seat belts ?? hood, fenders?
 
Not all 1975 models had the larger bolt pattern wheels.
Electronic ignition, catalytic converters, crash beams in the doors for better impact resistance....as mentioned, different interior door handle placement, interior door panel design, one piece cardboard headliner, etc.
All Dusters are great looking cars, in my opinion. I had a '74 that I modified to look like a 70-71 though.

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There would be a lot shorter list if you would ask what is the same. And they are very few cosmetic items.
Yes, they are very similar, but I was getting at more of the performance issues like mentioned detuned engines and extra weight. Seems to be like 300+ lbs more for the later model.
 
Yes, they are very similar, but I was getting at more of the performance issues like mentioned detuned engines and extra weight. Seems to be like 300+ lbs more for the later model.
I don't think there is a horsepower advantage for a 318 in '71 to a 318 in, lets say, '74. In general, the '70-'72 Duster are lighter, but not if we are talking the "feather lite" Dusters in '76. Also, options make a difference. No performance advantage in the transmissions, and rear ends are just a matter of which gearing. Of course, the early year Dusters could be optioned with a 8.75 rear vs 8.25 in the later years. Both early and late years rolled out millions of 7.25 rears in the Duster. Obviously, the newer ones had cats.
 
The only thing the 70 & 71 had an advantage with was the higher horse power 340 and Those ugly heavy bumpers. I also noticed the wire harness in the 74-76 was enormous compared to the 70 - 71 74 and newer had many connection problems . if the car sat in the elements. Probably due to a cheaper and less conductive connectors.
 
I have always thought they should be divided into generations.

Gen 1 should be 70 to 72 and gen 2 should be 73 to 76.

Very little is the same between the two other than same basic shape and the duster name.
 
most of the 70-1 cars with automatics had 904s, and so did the 75s, but the gear spacing was different - wider spacing of gears in the later cars. Later cars had lower 1st gears, somewhat lower second gears and the same 1:1 third gear. This was done to accommodate relatively high (numerically low) rear end gears (think 2.45:1). The lower first and second gears would cover up the high rear gears getting up to speed but result in lower engine rpms in third gear. You should figure out which gear set the 75 has before choosing rear gears (depending on your aims).

...and yeah the doors interchange between those years but they are completely different internally
 
Yes, they are very similar, but I was getting at more of the performance issues like mentioned detuned engines and extra weight. Seems to be like 300+ lbs more for the later model.

The rear bumper alone weighs about 88 lbs. That's the bumper, core, and shock mount brackets. At least that's what my '74's weighed. The non-shock '70-'72 bumpers without a crash core weigh about 1/3 that? Figure about 50 lbs extra. A '75 would have front and rear shock mounted bumpers, so just the bumpers by themselves would easily add over 100 lbs compared to '70-'72 bumpers. And the front's probably add more than the rears, my '74 didn't have a shock mounted front though so I don't have those weights.

There were also reinforcements added to the doors, a crash bar in the middle. I think that started in '74. My '74 has them at least. That adds a decent chunk of weight to the doors, it wasn't a couple lbs it was more like 10. You can tell the difference picking up a '70-73 door vs the '74, there were changes to all the window lift hardware as well which may have been part of it too. Then there was the extra electronic stuff, the smog stuff, etc. Adds up quick.

Some of the horsepower changes weren't just detuning either, there was a change in how the horsepower output was calculated. I think that was '73, I may be off by a year. The important part was that the biggest horsepower change year was also a change in the way the rating was done, the earlier ratings were without accessories, the later ones were with. So there was a decrease by all the belt driven stuff before any actual tuning changes. Although the compression ratio was lowered.

I have always thought they should be divided into generations.

Gen 1 should be 70 to 72 and gen 2 should be 73 to 76.

Very little is the same between the two other than same basic shape and the duster name.

I dunno about "very little", it's a lot more than just the "basic shape". The entire chassis is basically identical, only a couple of captured nut changes in the frame rails for the bumpers. All of the structural stuff was the same, minor changes to the quarters for the side markers (72+) and bumper lip change (74+). Roof skin was the same, rockers, etc. Floor got the bump for the catalytic convertor in '75, inner driver's side bucket seat track changed because of that, small change to the sheet metal for the 4 speed hump because of the bump for the cat. Minor changes here and there, passenger front inner fender got a "dent" for the charcoal canister, some hole location differences. Heater box changed (in '73) so resulting firewall hole changes.

The were changes to the engine mounts (spool type for 73+), the sway bar and tab locations on the LCA's. And the K changed to route the sway bar through the middle like the E's had already done. '73+ UCA's were the large ball joint style, disk brakes changed to use larger wheel bearings and single piston calipers. Drum brakes changed too, spindles took the large upper ball joints and the outer wheel bearings were larger but the drum/drum cars stayed SBP. But torsion bars and springs were the same, non sway bar LCA's were the same.

Power steering boxes went large sector, manuals were unchanged. Pitman, idler and center links changed, the tapers pointed down instead of up.

A lot of the differences aren't substantial in my book. Like, you can still bolt most of the parts on. They won't be "correct" for the given year, but they still fit. All the suspension parts swap out, lots of people upgrade the UCA's, spindles and brakes. Doors can be changed out as a whole. Same for the entire front clip sheet metal, minus the captured nuts for the bumper brackets. Like it's not that hard to make a '74 look like a '71, for example. If you nit pick, sure, you can tell some things are from a '74. But it's not like trying to bolt E-body parts on an A-body or something.

I guess it's perspective, if you're trying to be year correct there's a lot of minor changes. If you're trying to say, clone a '74 to look like a '71, well, the majority of the parts just bolt on.
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most of the 70-1 cars with automatics had 904s, and so did the 75s, but the gear spacing was different - wider spacing of gears in the later cars. Later cars had lower 1st gears, somewhat lower second gears and the same 1:1 third gear. This was done to accommodate relatively high (numerically low) rear end gears (think 2.45:1). The lower first and second gears would cover up the high rear gears getting up to speed but result in lower engine rpms in third gear. You should figure out which gear set the 75 has before choosing rear gears (depending on your aims).

...and yeah the doors interchange between those years but they are completely different internally
My 1976 duster 904 automatic has 2.45 first and 1.45 second gear ratios, same as the older cars. Wide ratios were not used until 1980 according to my transmission manual.
 
My 1976 duster 904 automatic has 2.45 first and 1.45 second gear ratios, same as the older cars. Wide ratios were not used until 1980 according to my transmission manual.
85, I think. A godsend for the 2.26(!) gears in M bodies.
 
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