1979 to 1975 parts interchange
10-03-2015, 12:30 PM
#1
Safety Car
Thread Starter
1979 to 1975 parts interchange
I'm looking at picking up a '79 today for a parts car.
Will the tilt column from the '79 work in my '75 ?
The rear differential is the same in '79 right? It was '80 that changed?
Bumpers the same?
-- Joe
Will the tilt column from the '79 work in my '75 ?
The rear differential is the same in '79 right? It was '80 that changed?
Bumpers the same?
-- Joe
10-03-2015, 01:15 PM
#2
Race Director
The column will work with a little bit of massaging. The 78-82 columns are a little shorter, than 69-75's. It's been done before, if you do a Forum search you should find some posts about how to do it.
All 65-79 rear ends are the same, and interchangeable.
75-79 front bumpers are identical. The rear bumper will fit with out modification, but it's not designed to accept your 75 rear Corvette emblem. The 75 bumper had indents molded into it for the individual C-O-R-V-E-T-T-E rear letters, while the 76-79 bumper is smooth, and has a one piece Corvette emblem that sits on top of the bumper cover, not in it.
All 65-79 rear ends are the same, and interchangeable.
75-79 front bumpers are identical. The rear bumper will fit with out modification, but it's not designed to accept your 75 rear Corvette emblem. The 75 bumper had indents molded into it for the individual C-O-R-V-E-T-T-E rear letters, while the 76-79 bumper is smooth, and has a one piece Corvette emblem that sits on top of the bumper cover, not in it.
10-03-2015, 08:55 PM
#3
Safety Car
Thread Starter
The column will work with a little bit of massaging. The 78-82 columns are a little shorter, than 69-75's. It's been done before, if you do a Forum search you should find some posts about how to do it.
All 65-79 rear ends are the same, and interchangeable.
75-79 front bumpers are identical. The rear bumper will fit with out modification, but it's not designed to accept your 75 rear Corvette emblem. The 75 bumper had indents molded into it for the individual C-O-R-V-E-T-T-E rear letters, while the 76-79 bumper is smooth, and has a one piece Corvette emblem that sits on top of the bumper cover, not in it.
All 65-79 rear ends are the same, and interchangeable.
75-79 front bumpers are identical. The rear bumper will fit with out modification, but it's not designed to accept your 75 rear Corvette emblem. The 75 bumper had indents molded into it for the individual C-O-R-V-E-T-T-E rear letters, while the 76-79 bumper is smooth, and has a one piece Corvette emblem that sits on top of the bumper cover, not in it.
I pulled this home today on the trailer. So the deal is, I bought it from this guys wife. Apparently the guy passed away in 2010. He was restoring the car.
It's a 4 speed manual. I'm assuming a M21 ?
Has the original aluminum rims
Has glass t-tops
Telescoping & tilting column
Rebuilt engine with camel hump heads, edelbrock intake, long tube headers, etc.
The body has some cracks. The frame has a rot spot behind the door in the usual place. The control arm mounting location looks ok.
I paid her $1000 for the car. I think I did ok.
I hate to strip it because it's complete, but between the cracks in the body and the frame I think it would be better to use some of the parts for my '75 restoration.
-- Joe
10-04-2015, 01:02 AM
#4
Race Director
At a thousand dollars, you surely did alright. If the glass tops are in good shape, they're worth $750-$800, and the aluminum wheels will bring $300 for the set. Sell them off and all the other parts are free!
If the car is an L-48, chances are the trans is a Saginaw wide radio (order code RPO M-20). Some L-48's did come with a wide ratio Super T-10 in 79, but if I remember right, only L-82's got the close ratio (M-21) Super T-10's. The Super T-10 is a great trans, the Saginaw not so much.
If the car is an L-48, chances are the trans is a Saginaw wide radio (order code RPO M-20). Some L-48's did come with a wide ratio Super T-10 in 79, but if I remember right, only L-82's got the close ratio (M-21) Super T-10's. The Super T-10 is a great trans, the Saginaw not so much.
10-04-2015, 05:46 AM
#5
Race Director
just bear in mind those bumpers are only 4 years younger than your current ones. unless they have been replaced, they are not really worth transplanting...
10-04-2015, 07:52 AM
#6
Le Mans Master
Member Since: Jul 2000
Location: Saginaw Michigan
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Later T&T into an early Shark
This paper has all you ever want to know about installing a later (1977 through 1982) Tilt & Telescoping steering column into an earlier (1969 through 1976) Vette.
http://jimshea.corvettefaq.com/?p=894
Good luck,
Jim
http://jimshea.corvettefaq.com/?p=894
Good luck,
Jim
10-04-2015, 08:15 AM
#7
Safety Car
Thread Starter
You guys are great, thank you!
I'll try to get the car on the lift this week to see what transmission it has. I still feel bad about parting it, but the tilt column alone for my '75 would be about $700 on ebay.
My rear bumper on my '75 like. vanished. It had some cracks. And slowly day by day I found pieces of it on the ground under the car. Very odd.
I actually like the dash in this '79 better than my '75, and it has an actual glove box. But I don't really dig the 'fast back' look.
-- Joe
I'll try to get the car on the lift this week to see what transmission it has. I still feel bad about parting it, but the tilt column alone for my '75 would be about $700 on ebay.
My rear bumper on my '75 like. vanished. It had some cracks. And slowly day by day I found pieces of it on the ground under the car. Very odd.
I actually like the dash in this '79 better than my '75, and it has an actual glove box. But I don't really dig the 'fast back' look.
-- Joe
10-04-2015, 09:18 AM
#8
Race Director
You guys are great, thank you!
My rear bumper on my '75 like. vanished. It had some cracks. And slowly day by day I found pieces of it on the ground under the car. Very odd.
I actually like the dash in this '79 better than my '75, and it has an actual glove box. But I don't really dig the 'fast back' look.
-- Joe
My rear bumper on my '75 like. vanished. It had some cracks. And slowly day by day I found pieces of it on the ground under the car. Very odd.
I actually like the dash in this '79 better than my '75, and it has an actual glove box. But I don't really dig the 'fast back' look.
-- Joe
10-04-2015, 11:54 AM
#9
Race Director
I wouldn't feel too bad about parting it. There were 49000 79's built. It was the highest production year ever, so they're not particularly rare. There really are (or were) a lot of them out there.
It does look like a decent car, and it might be a shame to part it out, so think of it this way, you're doing the owners of all of those other 79's a favor. Once you cut it up, their cars all just become a little rarer.
My rear bumper on my '75 like. vanished. It had some cracks. And slowly day by day I found pieces of it on the ground under the car. Very odd.
What ever the make up of the urethane was in those years, it tended to get brittle and crack. In 76, GM changed the urethane and the ones made since then seem to hold up very well. I've handled a lot of original, 35 year old bumpers, that still have plenty a flex to them. The only real issue with them is that the surface of them tends to get wavy.
This wasn't a Corvette only issue either. From your (modified) "screaming chicken" avatar, I'm guessing that you may have an affection for old Trans-Ams? The 74-75 Firebird's and Trans-Am's used the same urethane for their bumper covers, and suffered from the same problems. The flexible beak on the 73-75 Pontiac Grand-Am also suffered from this problem, and early 70's Cadillac's had a urethane bumper filler panel that cracked and fell apart. Not that many people care about or collect, 70's Sedan DeVille's.
10-04-2015, 03:36 PM
#10
Safety Car
Thread Starter
And a $700 tilt likely needs to be rebuilt. Restored/rebuilt 69-75 tilts go for $1000-$1300.
I wouldn't feel too bad about parting it. There were 49000 79's built. It was the highest production year ever, so they're not particularly rare. There really are (or were) a lot of them out there.
It does look like a decent car, and it might be a shame to part it out, so think of it this way, you're doing the owners of all of those other 79's a favor. Once you cut it up, their cars all just become a little rarer.
That's pretty typical of the 73-75 GM urethane bumper covers.
What ever the make up of the urethane was in those years, it tended to get brittle and crack. In 76, GM changed the urethane and the ones made since then seem to hold up very well. I've handled a lot of original, 35 year old bumpers, that still have plenty a flex to them. The only real issue with them is that the surface of them tends to get wavy.
This wasn't a Corvette only issue either. From your (modified) "screaming chicken" avatar, I'm guessing that you may have an affection for old Trans-Ams? The 74-75 Firebird's and Trans-Am's used the same urethane for their bumper covers, and suffered from the same problems. The flexible beak on the 73-75 Pontiac Grand-Am also suffered from this problem, and early 70's Cadillac's had a urethane bumper filler panel that cracked and fell apart. Not that many people care about or collect, 70's Sedan DeVille's.
I wouldn't feel too bad about parting it. There were 49000 79's built. It was the highest production year ever, so they're not particularly rare. There really are (or were) a lot of them out there.
It does look like a decent car, and it might be a shame to part it out, so think of it this way, you're doing the owners of all of those other 79's a favor. Once you cut it up, their cars all just become a little rarer.
That's pretty typical of the 73-75 GM urethane bumper covers.
What ever the make up of the urethane was in those years, it tended to get brittle and crack. In 76, GM changed the urethane and the ones made since then seem to hold up very well. I've handled a lot of original, 35 year old bumpers, that still have plenty a flex to them. The only real issue with them is that the surface of them tends to get wavy.
This wasn't a Corvette only issue either. From your (modified) "screaming chicken" avatar, I'm guessing that you may have an affection for old Trans-Ams? The 74-75 Firebird's and Trans-Am's used the same urethane for their bumper covers, and suffered from the same problems. The flexible beak on the 73-75 Pontiac Grand-Am also suffered from this problem, and early 70's Cadillac's had a urethane bumper filler panel that cracked and fell apart. Not that many people care about or collect, 70's Sedan DeVille's.
The column appears to be in really good shape. No slop or anything. Car had 80k on it. I hope I won't have too much trouble painting it black.
The seats are WAY nicer than my '75 seats in terms of comfort. But they are red...
The doors are really nice too. Too bad they are different that my '75.
Is the parking brake mechanism the same? My parking brake on the '75 doesn't work at all.
So the frame is rotted in two spots. A small nickle size hole in the front, but more importantly the rear behind the door where the body mounts. Here is a few shots from under the car. (eeek!)
10-04-2015, 04:30 PM
#11
Race Director
ok, that 79 is either a new frame or a parts car. the doors should interchange.
10-04-2015, 06:22 PM
#12
Safety Car
Thread Starter
The doors do but the door panel and latch locations are different if I recall. ?
I was under the impression you couldn't put '75 door panels on like a '78 or newer ?
Anyhow. I crawled under it and checked, the transmission is a T10.
-- Joe
10-04-2015, 08:30 PM
#13
Race Director
The panels are different, and not interchangeable. Otherwise, the 79 doors are a direct bolt on to your 75, but the inside release mechanism is completely different. You can convert the doors over to the earlier mechanism, but I doubt it's worth it. The time and labor spent converting the doors, could just as easily be spent repairing your 75 doors.
The Super T-10 is a plus, especially over the Saginaw trans.
10-07-2015, 01:07 PM
#14
Safety Car
Thread Starter
I'm really tempted to put the 4spd and the alum rims on my '75, vs the TH400 and the ralley rims.
How bad is swapping the entire dash? Like, is the mounting points on the firewall the same or ?
Other than the condition of the body (cracks) and the frame (rot), I like the '79 a lot interior and option wise.
I gotta get this firechicken finished and off my lift so I can get one of these cars in and apart.
-- Joe
How bad is swapping the entire dash? Like, is the mounting points on the firewall the same or ?
Other than the condition of the body (cracks) and the frame (rot), I like the '79 a lot interior and option wise.
I gotta get this firechicken finished and off my lift so I can get one of these cars in and apart.
-- Joe
10-07-2015, 07:09 PM
#15
And a $700 tilt likely needs to be rebuilt. Restored/rebuilt 69-75 tilts go for $1000-$1300.
I wouldn't feel too bad about parting it. There were 49000 79's built. It was the highest production year ever, so they're not particularly rare. There really are (or were) a lot of them out there.
It does look like a decent car, and it might be a shame to part it out, so think of it this way, you're doing the owners of all of those other 79's a favor. Once you cut it up, their cars all just become a little rarer.
That's pretty typical of the 73-75 GM urethane bumper covers.
What ever the make up of the urethane was in those years, it tended to get brittle and crack. In 76, GM changed the urethane and the ones made since then seem to hold up very well. I've handled a lot of original, 35 year old bumpers, that still have plenty a flex to them. The only real issue with them is that the surface of them tends to get wavy.
This wasn't a Corvette only issue either. From your (modified) "screaming chicken" avatar, I'm guessing that you may have an affection for old Trans-Ams? The 74-75 Firebird's and Trans-Am's used the same urethane for their bumper covers, and suffered from the same problems. The flexible beak on the 73-75 Pontiac Grand-Am also suffered from this problem, and early 70's Cadillac's had a urethane bumper filler panel that cracked and fell apart. Not that many people care about or collect, 70's Sedan DeVille's.
I wouldn't feel too bad about parting it. There were 49000 79's built. It was the highest production year ever, so they're not particularly rare. There really are (or were) a lot of them out there.
It does look like a decent car, and it might be a shame to part it out, so think of it this way, you're doing the owners of all of those other 79's a favor. Once you cut it up, their cars all just become a little rarer.
That's pretty typical of the 73-75 GM urethane bumper covers.
What ever the make up of the urethane was in those years, it tended to get brittle and crack. In 76, GM changed the urethane and the ones made since then seem to hold up very well. I've handled a lot of original, 35 year old bumpers, that still have plenty a flex to them. The only real issue with them is that the surface of them tends to get wavy.
This wasn't a Corvette only issue either. From your (modified) "screaming chicken" avatar, I'm guessing that you may have an affection for old Trans-Ams? The 74-75 Firebird's and Trans-Am's used the same urethane for their bumper covers, and suffered from the same problems. The flexible beak on the 73-75 Pontiac Grand-Am also suffered from this problem, and early 70's Cadillac's had a urethane bumper filler panel that cracked and fell apart. Not that many people care about or collect, 70's Sedan DeVille's.
Excellent info! You mentioned the urethane material was changed at some point . Do you think the replacement 73-74 cover were also manufactured using the better material too latter on in the eighty 's after the old original stock ran out ? I bought a GM replacement around 1991 NOS . They were still available from the dealer . I think the label had like 1987 or so on it. Anyway ....that frt cover is still holding up very well....so far ......the change in material might explain it ....?
10-07-2015, 07:24 PM
#16
Safety Car
Thank you. Hopefully I can get the covers off without tearing them. They seem pretty good, although I do notice some waves. My '75 isn't exactly a collector item either so if I can save money here and there it's good.
The column appears to be in really good shape. No slop or anything. Car had 80k on it. I hope I won't have too much trouble painting it black.
The seats are WAY nicer than my '75 seats in terms of comfort. But they are red...
The doors are really nice too. Too bad they are different that my '75.
Is the parking brake mechanism the same? My parking brake on the '75 doesn't work at all.
So the frame is rotted in two spots. A small nickle size hole in the front, but more importantly the rear behind the door where the body mounts. Here is a few shots from under the car. (eeek!)
The column appears to be in really good shape. No slop or anything. Car had 80k on it. I hope I won't have too much trouble painting it black.
The seats are WAY nicer than my '75 seats in terms of comfort. But they are red...
The doors are really nice too. Too bad they are different that my '75.
Is the parking brake mechanism the same? My parking brake on the '75 doesn't work at all.
So the frame is rotted in two spots. A small nickle size hole in the front, but more importantly the rear behind the door where the body mounts. Here is a few shots from under the car. (eeek!)
10-07-2015, 08:14 PM
#17
Race Director
It's fixable because it has a lot of good metal around it. The car must have been in the rust belt because that's where the salt lays in the frame. Everything is reproduced as far as frame sections go. The body mounts would need to be done regardless. Tear into it a little and see what it would take to get it road worthy. A driving 79 is worth about $4-5000 that's a pretty good profit. Better than having parts all over your yard waiting on eBay buyers
10-07-2015, 08:22 PM
#18
Race Director
I'm really tempted to put the 4spd and the alum rims on my '75, vs the TH400 and the ralley rims.
How bad is swapping the entire dash? Like, is the mounting points on the firewall the same or ?
Other than the condition of the body (cracks) and the frame (rot), I like the '79 a lot interior and option wise.
-- Joe
How bad is swapping the entire dash? Like, is the mounting points on the firewall the same or ?
Other than the condition of the body (cracks) and the frame (rot), I like the '79 a lot interior and option wise.
-- Joe
10-07-2015, 10:22 PM
#19
Safety Car
Thread Starter
I can get a frame for a few hundred bucks, there is a few on craigslist.
The biggest problem is the body. There is cracks in a lot of spots, many of them going to the wheel lips. The rear quarters kinda flap as the parts that hold them in the center are broken.
My '75 is straight as an arrow, no cracks, in primer.
If it was frame OR body, I'd do either. I feel like with both I'd have too many hours into it.
-- Joe
The biggest problem is the body. There is cracks in a lot of spots, many of them going to the wheel lips. The rear quarters kinda flap as the parts that hold them in the center are broken.
My '75 is straight as an arrow, no cracks, in primer.
If it was frame OR body, I'd do either. I feel like with both I'd have too many hours into it.
-- Joe