1971 Corvette engine ID question.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,297
Likes: 156
From: Clayton New Jersey
1971 Corvette engine ID question.
This is probably a dumb question but here goes, How do you know what engine came originally in a 71 Corvette. My 71 has a big block hood and rear sway bar. It currently has a small block 350 that is not numbers matching. Is there any way to tell? I read the 71 vin only states its a V8.
Team Owner
Joined: Sep 2006
Posts: 31,315
Likes: 4,418
From: Westminster Maryland
Hi HT,
The only sure way is through the information on the tank sheet.
But, the car itself will offer some clues… configuration of the radiator, fuel lines, tachometer, rear yokes and half shafts, sway bars….all varied depending on the engine that was in the car when it left St.Louis.
There are some threads here describing the specifics of just what to look for in each area.
The NCRS 70-72 TIM&JG would also be a source for just what to look for to perhaps determine just what engine your car had originally.
Regards,
Alan
The only sure way is through the information on the tank sheet.
But, the car itself will offer some clues… configuration of the radiator, fuel lines, tachometer, rear yokes and half shafts, sway bars….all varied depending on the engine that was in the car when it left St.Louis.
There are some threads here describing the specifics of just what to look for in each area.
The NCRS 70-72 TIM&JG would also be a source for just what to look for to perhaps determine just what engine your car had originally.
Regards,
Alan
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
What's the redline on the tach?
5300rpm - 350/270hp (no sway bar, two fuel lines)
6500rpm - 350/330hp (no sway bar, one fuel line)
5600rpm - 454/365hp (sway bar, two fuel lines)
6500rpm - 454/425hp (sway bar, two fuel lines)
5300rpm - 350/270hp (no sway bar, two fuel lines)
6500rpm - 350/330hp (no sway bar, one fuel line)
5600rpm - 454/365hp (sway bar, two fuel lines)
6500rpm - 454/425hp (sway bar, two fuel lines)
Last edited by Revi; Jun 12, 2015 at 10:46 AM.
Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
Melting Slicks
Joined: Apr 2007
Posts: 3,189
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From: Tolland CT
Yes, all parts could be bought from the dealer to build a big block clone. In this case I'd wonder why someone would do that, then install a small block, especially the tach, yokes on the differential, and a variety of other parts. Doesn't seem likely. Now if the car had a big block today with a blank numbers pad, then I'd wonder if someone built a clone. Assuming the tank sheet is missing...
Administrator
Joined: Jul 2000
Posts: 54,006
Likes: 6,215
From: About 1100 miles from where I call home.
Adding a BB /LT1 hood is pretty common for looks sake.
Changing the tach, with the 350 replacement in the car, seems far more unlikely. So are yoke changes.
Is there a data plate on the shifter console?
Changing the tach, with the 350 replacement in the car, seems far more unlikely. So are yoke changes.
Is there a data plate on the shifter console?
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,297
Likes: 156
From: Clayton New Jersey
It has the 5300 rpm tach. What radiator came with the 350/270? I have the original it's a 4 core..(no AC) is that correct for the small block?
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Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
Base engine, automatic and/or A/C. Larger copper radiator without expansion tank.
Last edited by Revi; Jun 13, 2015 at 09:11 AM.
Le Mans Master
Joined: Feb 2001
Posts: 6,317
Likes: 292
From: Ocala FL
A little history lesson. In 1973 and in 1975, there were "huge" jumps in gas prices due to oil embargoes. As such, people with gas guzzling 8 mpg big blocks occasionally yanked them and replaced with generic SBC which got 13 - 15 mpg. After all, gas was up to 50 cents a gallon for regular.
Outrageous.
On rear ends, people drove these cars back then, and often hard. If you blew a rear end, you could rebuild it for a couple hundred dollars or you could buy a used one for $100. The first was more money and the car was down for a couple of days; the second was cheaper and you'd be running in a few hours.
No one cared if the numbers matched back then, so a big block cap and bolt rear, or a rear from the later years would work just as well as a u-bolt rear.
Don't discount the tank sticker being gone, unless you know the tank was replaced. People have frequently thought they were long gone, only to find them in restoration several years later. If they had looked earlier, they would have probably been in better condition.
Outrageous.
On rear ends, people drove these cars back then, and often hard. If you blew a rear end, you could rebuild it for a couple hundred dollars or you could buy a used one for $100. The first was more money and the car was down for a couple of days; the second was cheaper and you'd be running in a few hours.
No one cared if the numbers matched back then, so a big block cap and bolt rear, or a rear from the later years would work just as well as a u-bolt rear.
Don't discount the tank sticker being gone, unless you know the tank was replaced. People have frequently thought they were long gone, only to find them in restoration several years later. If they had looked earlier, they would have probably been in better condition.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,297
Likes: 156
From: Clayton New Jersey
Looked for the tank sticker using a mirror and flashlight. ..could not see one. I did see written in yellow..on the area in front of the gas tank..the date 11-6-1970.
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
A little history lesson. In 1973 and in 1975, there were "huge" jumps in gas prices due to oil embargoes. As such, people with gas guzzling 8 mpg big blocks occasionally yanked them and replaced with generic SBC which got 13 - 15 mpg. After all, gas was up to 50 cents a gallon for regular.
Outrageous.
On rear ends, people drove these cars back then, and often hard. If you blew a rear end, you could rebuild it for a couple hundred dollars or you could buy a used one for $100. The first was more money and the car was down for a couple of days; the second was cheaper and you'd be running in a few hours.
No one cared if the numbers matched back then, so a big block cap and bolt rear, or a rear from the later years would work just as well as a u-bolt rear.
Outrageous.
On rear ends, people drove these cars back then, and often hard. If you blew a rear end, you could rebuild it for a couple hundred dollars or you could buy a used one for $100. The first was more money and the car was down for a couple of days; the second was cheaper and you'd be running in a few hours.
No one cared if the numbers matched back then, so a big block cap and bolt rear, or a rear from the later years would work just as well as a u-bolt rear.
The two items I wouldn't think someone would normally swap which may indicate a big block would be the tach and radiator support, larger radiator. The radiator is a lesser indication, someone may have wanted extra cooling. All other parts as mentioned could have been swapped if the original was blown, nobody cared back then.I do recall at least one fellow who replaced a big block in a C2 with a small block to increase gas mileage back in that day. It did happen, probably fairly often around the time of the Arab oil embargo, gas lines, rationing, etc.
Team Owner
Joined: May 2005
Posts: 31,497
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From: Huntsville AL
I recall seeing a 71 454 coupe that came back from Puerto Rico. I guess gas is expensive in Puerto Rico. The car had a 250 straight 6 cylinder engine in it.
It was actually kind of cool. You could actually work on that engine.
It was actually kind of cool. You could actually work on that engine.