How can you tell if a C3 has an L-48 or an L-82 motor?

 

My 1976 vette has the original plate on the console - says L48.

Might sound like too easy answer, but thats the first place I'd look.

I've read threads in the tech forum ages ago about how to tell the difference. Try searching and see what you can come up with.

 

Engine suffix

http://www.corvette-world.com/corvet...tion_codes.php

 

Exactly. Stamped on the block pad at the front of the right head. Some VINs have engine codes but that does not guarantee the engine hasn't been replaced. Console tags are easy to replace. Engine suffix will identify the engine and it's original application.

 

Two easy & quick ways to tell. If the motor is original & untouched, the L48 has a cast iron intake and tin value covers painted the same color as the block. The L82 will have an aluminum intake & finned valve covers painted black.

 

Im not really sure but the tachs may have different redlines.The L82 might rev a little higher.

 

...and it says "L-82" on tach face near bottom..

 

I think it's the 5th digit of the VIN that identifies whether it's an L-82 or not, but I cant remember what it should be here at work.

 

My 79 says "L-82" in big red letters on top of the hood

 

The Vin will have a "X" in the 5th or 6th spot for a L-82.

 

Sorry Jim...

The aluminum intake was not re-introduced until the 1978 model... before that the L82 had the same cast iron manifold as the L48. No aluminum manifolds came on Corvette 350's from '73 thru '77.

GUSTO

 

you have to get in the car and floor it...


I was kidding but is there a big difference?

 

I've always wondered that myself.

Theres a guy in our club with an L82 and I have a L48, he says he has trouble keeping up, but my reply is maybe your engine needs some attention.

It would be good to get a side by side comparison on two similar condition cars with the different motors. In the black book (for 76) there is nearly a 100hp difference, but who knows.

 

Yes thats the only real way to find out. Different years have different cosmetic features also........LT

 

It's closer to 30hp difference.

(Stop removing your helmet during combat practice)

Greg

 

So does mine, as does the console plate. But it's a L-48.

Anyone can easily change either of these two things. A better ID would be the 5th digit VIN number where a "J" is an L-48 and a "T" is an L-82. Or at least that is how it left the factory. After that, all bets are off.

Good Luck!

 

Yup, it the 5th digit of the VIN that provides the clear determination. It varied by year, so consult the Corvette Black Book, ie. in 1980 the fifth digit was a 6 for the L89; a 8 for the L48; and a H for the 305 California car: 230, 190 and 180 HP, respectively. The L89 and L48 both had the same aluminum intake manifold, and I'll bet the 305 did too. The L89 had a more aggressive cam, I think 218/218 @ 50, and probably flat top pistons to reach 9.0:1 compression, and a 4 bolt main.

 

I stand corrected - I just checked the book and it is:

L-48 = 180hp
L-82 = 210hp

Like you said, 30 difference.

 

This is correct; all the other stuff can easily be faked. This number will appear in the A pillar and it will also be stamped on the engine. On my ’75 it’s stamped on a boss that I believe is located on the driver side of the block, at the front of the engine. The HP increase is really not much to speak of with an L-82. There production numbers are less than the L-48s though. If that really means something though, I’m not sure. They don’t seem to sell for much more than the standard version.

 

Not exactly. The character in the VIN identifying the engine varied in the C3 years. For example, my 73 has a "T" identifying the motor as an L82. Also, the VIN only indicates what the motor was at birth. Like others have said above, you must look at the 3-character suffix at the end of the engine stamp. That will identify the motor and tranny combination.