Year by year breakdown.

by Podor Sun Sep 03, 2017 9:29 am

This may have already been addressed in another post, but I couldn't find one. I know there are changes year to year in a production run. I was wondering if there was a breakdown of what changed year by year on the Chevelles, and how it related to other G3 A bodies?

This is what I understand so far on the Chevelle side, and correct me if I'm wrong. Please add detail, especially on the mechanical side.
73 to 74
Grill extended to hood line.
SS and laguna dropped laguna S-3 introduced
Rear bumper changed to include shocks
Trapazoid taillights from round
74 to 75
Slightly different grill
S-3 gets raked nose
Catalytic Converter added, single relief cross member
454 dropped
Rectangular taillights
75 to 76
Slightly different grill
Stacked square headlights for Classics
400 dropped
305 2 barrel added as base V8- engines corperate blue instead of Chevy orange
Chrome radio and headlight nobs instead of black rubber
76 to 77
Slightly different grill
S-3 dropped
6 section rectangular taillights

by clanceman427 Sun Sep 03, 2017 9:48 am

For 73 to 74:
- the rear panel changed from sheetmetal welded to fiberglass bolt on, thus changing the rear quarter panels with it while moving the rear marker lights slightly.
-Front inner fenders go from plastic to metal
-I think the retractable front shoulder belts debuted in 74

74-75
-HEI ignition standard
-4 speed manual transmission no longer offered

Great thread, fun. Looking forward to hearing more year by year

by pila Sun Sep 03, 2017 12:16 pm

My '74 had the point type ignition ( still have that engine, 350, as removed ) Was the HEI offered as an option in '74 ??)

Bill

by Joe73 Sun Sep 03, 2017 12:34 pm

Off the top of my head. But spending time on gmheritagecenter would yield more info. And obviously there have to be "overlaps" in an option meaning they might still use a part in a, for example, a 75 model that was actually being built in 74.

So off the top of my head,

73 one year only parts. Complete header panel, front and rear bumpers with filler panels, front bumper shocks (side mount bolts), front lower control arm bushings had two different sizes early vs. late, dashboard although physically the same it had a bolt on pass side emblem which 74 and later didnt. As stated above, tail light panel. 73 trunk pan is one year only. All 73 "A" bodies only had 14" tires only. Also as stated, 73 only plastic front wheel wells. 73 only came with stainless triangle window trim if ordered. Later years had plastic. 73 swivel buckets do not have the shoulder belt guide because no roof mounted re tractor, as stated above. 73 antifreeze overflow bottle is one year only. 73 only horn relay.

73-74 round cluster used an amp gauge or light which later switched to volt gauge.
73-74 trunk lid, although the same, 74 used different closing latch or something.
73-74 only for a manual transmission.
73-74 offered a "neutral" interior color. Later years got actual white.
73-74 only had the double hump crossmember since 75 started catalytic.

75-77 Catalytic converter started in 75 hence the different crossmember
75-77 HEI was introduced. But there are original late built 74 cars with HEI.
75-77 round gauge cluster could have an "economy" vacuum gauge.
75-77 inside floor seat crossmember and pass side swivel seat, inside front mounting bolt bracket is different.

by clanceman427 Sun Sep 03, 2017 1:29 pm

Excellent info Joe! Question: what made the 73 radiator overflow tank unique? Was it how it mounted to the 73-only plastic inner fender?

by Joe73 Sun Sep 03, 2017 1:32 pm

74 bottle is a totally different shape due to the metal wheel well. 74 is mostly square. The 73 plastic well has a flat vertical area. 74 are more rounded.

by clanceman427 Sun Sep 03, 2017 3:32 pm

Cool my car's was missing when I got it so I bought one on-line and it definately was a correct 73 then.

by Podor Sun Sep 03, 2017 4:07 pm

pila wrote:My '74 had the point type ignition ( still have that engine, 350, as removed ) Was the HEI offered as an option in '74 ??)

Bill

This is great! Thanks and keep it coming.

My '74 was points. It switch late in the model year. I looked at a '74 with OE HEI a few weeks ago.
I forgot about the starter interlock with the seat belt in '74. You had to have you're seat belt on to start the car. I think that was '74 only.

by Mcarlo77 Sun Sep 03, 2017 5:51 pm

Nope...starter interlok carried over into the first half of the '75 model year. My Laguna had it...and, I've seen many other '75's with it in the junk yards. Terrible idea.

by Podor Sun Sep 03, 2017 6:29 pm

Mcarlo77 wrote:Nope...starter interlok carried over into the first half of the '75 model year. My Laguna had it...and, I've seen many other '75's with it in the junk yards. Terrible idea.

Great theft deterrent, lol.

A few other observations
75
100 Mph speedometer instead of 120
76-77
"Max" AC setting added - full fan, recerculate and heater bypass active
"squared" steering wheel contuur with wood grain insert

by Podor Sun Sep 03, 2017 6:37 pm

I'm assuming the El Camino/Sprint is pretty similar. I know the SS carried long past the Chevelle, until 75? Did they ever have the Laguna front clip?

by Joe73 Sun Sep 03, 2017 8:30 pm

The laguna front clip on an el camino has been debated. But I've seen caminos with the laguna clip along with the build sheet. It could be ordered. Although I've never researched it on gmheritage to see if it was even listed as an option.

by Mcarlo77 Sun Sep 03, 2017 8:42 pm

El Caminos and Sprints carried over the '73 style shoulder straps until '76/'77...after which they followed suit with the coupes/sedans and went to retractors.

by 77camino Sun Sep 03, 2017 9:43 pm

The SS continued on the El Camino through the 77 on the G3. Not sure if it was available every year but the SS continued until the shut down in 88. GM made a Super Sport and Choo Choo customs made the SS version based off of the Monte. My 77 does have retractor seat belts.

by fasrnur Mon Sep 04, 2017 5:36 pm

Great job there Joe! You have a very vast knowledge of these cars and it's great to have you here to help all of us that are just learning about them.

I have a question in regards to the plastic inner fenders and overflow tank.
If one were to switch from metal to plastic inner fenders, would they have to get the 73 overflow bottle then?

Thanks again for all the help Joe.

by Joe73 Mon Sep 04, 2017 5:59 pm

I've had 10 73 chevelles that I parted over the years.
I would think that if you switch from metal to plastic or the other way around, you could probably use the same overflow bottle since the bottle has a hose going to the bottom. So it should work. But it wouldnt look right and you would have to drill an extra hole to mount it correctly.

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