This has probably been discussed before but I am not sure how to search for it. Here is a easy question for the experts.

What are the visual and mechanical differences between the 70, 71 and 72 verts?

I owned a 70 which I sold in 76 to pay the bills from a divorce but that is a whole nother story. Ready to make the move again (vette, not marriage) but do not remember what the differences were between these three years.

 

Highest horsepower in 70 except for 71 LS6

70-300,350,370,390 hp

71-270,330,365,425 hp

72-(net ratings)-200,255,270

70 and 71 look same, some minor differences

72 had no fiberoptics, engines rated at net instead of gross hp, amber park lenses, standard alarm

Of course different exterior/interior overall color choices each year

 

As I recall, '70 and '71's had clear turn signals up front. Later production '71's and '72's had amber turn signals. All '72's had the security system in the rear. It was an option on other years.
You might be able to tell apart the years by color options too...
Other than that, I can't visually distinguish what would be different among the 70, 71 & 72's...Unless you look under the hood!

 

Engine options dwindled as time went on in Corvette. Horsepower went to net horse power in 1972 which made it look like a big drop in horsepower. Compression ratios went down to make way for unleaded fuel. 1972 Alarm was standard but fiber optics were gone because of this. 1971 fiberglass was more difficult to repair due to some change in fiberglass resin. 1972 was the last year of the chrome bumper cars front and back with removable rear window. All of the above is applicable to a factory correct car as lots of these cars have been modified

 

There are a lot of minor changes between the '70, '71 & '72 model years. However 1971 is the most difficult to pin down, as it is a transition year for a lot of these changes, in other words, 1971's have both '70 & '72 characteristics, depending if a early run model or late run model.

Looking at VIN plate through winshield best for accurateness. Anyway here are some of the changes.

1970 unique side louver (did not match front grille style) also EARLY '71's
1970 conical style center tail lamp lens (also EARLY '71's)
1970 front grilles cast stud posts (also EARLY '71's)
1970 headlamp washer system
1970 clear/opaque front lenses (also 1971's)

1972 side louver design change (matched front grille design) also 1971.
1972 rounded tail lamp lenses (also '71's)
1972 front grilles use mounting screws (also '71's)
1972 amber front lenses (also '71's)

1971 different style data plate (same as '70)
1971 stainless trim on pedals (same as '70)
1971 chrome plate plastic vent control ***** (same as '70)
1971 fiberoptics panel (same as '70)
1971 instrument lettering color (same as '70)


1972 unique items

Custom interior seat pleating '72 only...'70 & '71 same
Radio ***** and stereo insignia '72 only... '70 & '71 same
accelerator pedal style '72 only... '70 & '71 same
data plate design '72 only.... '70 & '71 same
seat belt design '72 only... '70 & '71 same
instrument cluster panel '72 only... '70 & '71 same


The list could continue, but this gives you an idea.

 

I would go for the 70 454 auto coupe but that's me. The LT-1 is a hot one but you will have to shift with that and Air Cond on that engine wasn't available until 1972.

 

Is there any quick way to tell the year when you meet it going down the highway or see in in passing?

 

The amber turn signals are about the only way you'll be able to in that situation...

 

Thanks for all the replies. I remember some of the differences now that you guys listed them but there are a lot that I didn't know.

 

This is a good list... I have a 71 and a 72. The differences are there but he 70 and 71 are very hard to tell apart.....but there are very small changes from 70 to 71, without the front lenses some experts can't tell them apart.

Jim

 

On the 72 you will see a alarm keyhole in the middle of the rear between the tail lights. Amber turn signals coming at you on 72.
On front coming at you 70/71 had clear lense turn signals.

 

The visual difference between 70 and 71 while driving toward each other is hard to notice. If you look at the chrome surrounding the front grills 71 shows screw heads at the bottom 70 does not. Plus the items mentioned above my .02 WB

 

I have read and do believe that some later 70's had screws in lower section. Remember this was a late year to begin production (70 1/2) due to strike. The 70 and 71 according to my books have a lot of changes based upon when they were produced. I have one original grill (pretty confident it was original) and it had holes in bottom. Mine is in excess of 10,000 in a production year with <15k. Also. late 70's had different stickers in front of driver on head wall, later production and 71had two stickers a white with a yellow sticker below. Some books indicate that some late 70 models had the snorkel intakes on base engine. However mine does not have snorkel. Alarm switch is in same place on all 70 models, but early ones had a differnet switch than later models. Mine happens to have the earlier style (found this out when I went to buy a new switch). But except for engine horse power and smog pump added in 71 on base engine, the 70 and 71 are very similar, based upon when it came off the line.

 

given the choice would you rather have the fiber optic system on 70 and 71 Corvette or the alarm system on 72 Corvette?

 

No question - the fiber optic indicator lights! All of mine work and I love it at night, but I wonder how many original alarms still function?

 

It isn't that great of an alarm anyway only uses pin switches. One could easily stick their body inside after breaking a window and it won't go off. It is also easy to dismantle that alarm.
How do the fiber optics work in that I mean do they stay lit up and if it isn't does that mean it is burned out?

 

The fiber optic monitors the bulb it is looking at. The FO cable is just a light pipe, if you want to call it that. If the bulb goes out then the light made by the bulb does not travel the fiber optic cable, thus the FO cable emits no light at the console.

 

The fiberoptic monitoring system is a really neat item. It indicates to the driver whether headlamps, tailamps, signal lamps, brake lights, hi-beam lights & license lamp are working! Different colors are used and at night looks very cool. Reminds me of running lights on commerical aircraft.

 

It must look fascinating like a Christmas tree

 

The greatest difference between these particular years is the compression ratio of the engines. Because of emissions/fuel issues, GM dropped CR from the 10-11 range down to the 8.5-9.5 range. The engines in 1971 and 1972 weren't really that much different, but horsepower ratings changed from "gross" to "SAE net". Because of that the book ratings were vastly different, thus, folks think the engines are different.
The '70 & '71's had clear front parking light lenses with amber bulbs; the '72's had amber lenses with clear bulbs.
The rest of the differences are minor cosmetics, paint color differences, and option alterations that have already been mentioned.
P.S. Because of the "real" power differences between 70's and the others, the sale value of the '70's is usually higher. However, you could get A/C with the LT1 in 1972 but not in the other years. And if you can locate and 1972 LT1 with a working A/C....that would be a real find!

7T1VETTE