What is the difference!?
Thread Starter
Safety Car
Joined: Nov 2006
Posts: 4,449
Likes: 0
What is the difference!?
what is the diff. between the L-48 and the L-88 mechanicaly? i know the obvious HP difference, would it be possible to "transform" my L-48 into an L-88? im thinking begger CAM push rods, springs, rocker arms etc etc, but wut else?
Miles
Miles
Le Mans Master
Joined: Oct 2005
Posts: 9,429
Likes: 44
From: Macon, GA
You mean L82?
L48 - 2 bolt main block
Years: 1970-1980
The L48 was the standard engine on the 1971 Chevrolet Corvette. It produced 270 hp (201 kW) and 360 ft·lbf (477 N·m) with an 8.5:1 compression ratio.
The 1976-1979 L48 was the standard Corvette engine and produced 180 hp (134 kW) and 270 ft·lbf (366 N·m). The 1980 L48 stood at 190 hp (142 kW) and 280 ft·lbf (380 N·m) from 8.2:1 compression.
In 1973 the "L-48" had cold air induction (throttle activated) and developed 190 hp (net). Beginning in 1974 the hp was reduced for several years until it reached a low of 165 (net) in 1975 or '76, before rising again.
L82 - 4 bolt main block, forged crank
Years: 1973-1980
The 1973-1974 L82 was a "performance" version of the 350 producing 250 hp (186 kW) and 285 ft·lbf (386 N·m) from 9:1 compression. It was down to 205 hp (153 kW) and 255 ft·lbf (346 N·m) for 1975. It was the optional engine again in 1976-1977, producing 5 hp (4 kW) more. The 1978 L82 recovered somewhat, producing 220 hp (164 kW) and 260 ft·lbf (353 N·m), and 5 hp (4 kW) and 10 ft·lbf (14 N·m) more for 1979. 1980 saw another 10 hp (7.5 kW) and 15 ft·lbf (20 N·m).
L48 - 2 bolt main block
Years: 1970-1980
The L48 was the standard engine on the 1971 Chevrolet Corvette. It produced 270 hp (201 kW) and 360 ft·lbf (477 N·m) with an 8.5:1 compression ratio.
The 1976-1979 L48 was the standard Corvette engine and produced 180 hp (134 kW) and 270 ft·lbf (366 N·m). The 1980 L48 stood at 190 hp (142 kW) and 280 ft·lbf (380 N·m) from 8.2:1 compression.
In 1973 the "L-48" had cold air induction (throttle activated) and developed 190 hp (net). Beginning in 1974 the hp was reduced for several years until it reached a low of 165 (net) in 1975 or '76, before rising again.
L82 - 4 bolt main block, forged crank
Years: 1973-1980
The 1973-1974 L82 was a "performance" version of the 350 producing 250 hp (186 kW) and 285 ft·lbf (386 N·m) from 9:1 compression. It was down to 205 hp (153 kW) and 255 ft·lbf (346 N·m) for 1975. It was the optional engine again in 1976-1977, producing 5 hp (4 kW) more. The 1978 L82 recovered somewhat, producing 220 hp (164 kW) and 260 ft·lbf (353 N·m), and 5 hp (4 kW) and 10 ft·lbf (14 N·m) more for 1979. 1980 saw another 10 hp (7.5 kW) and 15 ft·lbf (20 N·m).
Last edited by sperkins; Apr 12, 2007 at 11:42 AM.
Drifting
Joined: Nov 2006
Posts: 1,437
Likes: 6
From: Perth West Australia
St. Jude Donor '11-'12
Miles,
You could rebuild your engine with higher compression pistons to give around 10:1 compression ratio, an RV cam with a lift of around .490 and stronger double valve springs. Open the ports of the heads up a little and then polish them and you will have more horsepower from the engine than the L82. The advantage of this type of build is you maintain driveability and can run premium pump gas and retain a stock appearing motor. When you have the funds available replace the stock headers and the inlet manifold and go bigger on the carburettor.
After that it is how deep are your pockets and how fast do you want to go.
Have a great day and enjoy that vette.
You could rebuild your engine with higher compression pistons to give around 10:1 compression ratio, an RV cam with a lift of around .490 and stronger double valve springs. Open the ports of the heads up a little and then polish them and you will have more horsepower from the engine than the L82. The advantage of this type of build is you maintain driveability and can run premium pump gas and retain a stock appearing motor. When you have the funds available replace the stock headers and the inlet manifold and go bigger on the carburettor.
After that it is how deep are your pockets and how fast do you want to go.
Have a great day and enjoy that vette.
Thread Starter
Safety Car
Joined: Nov 2006
Posts: 4,449
Likes: 0
thanks guys, question awnsered! like my dad says every time he see's me on the forum: "that thing is so great for you, you hav so much information within such an easy grasp"
i love this place!
Miles
i love this place!
Miles
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Racer
Joined: Mar 2007
Posts: 306
Likes: 0
From: New Hampshire
Ya, just a better cam, 4 bolt main and different pistons for a higher Comp. ratio, otherwise both blocks
from, I believe 1969 were 3970010's. Most years the heads were the same also except for bigger valves in L-82.
from, I believe 1969 were 3970010's. Most years the heads were the same also except for bigger valves in L-82.
Racer
Joined: Mar 2007
Posts: 306
Likes: 0
From: New Hampshire
TOM73, that is a great example. I put my 2 cents in before seeing your thread. I think from 74 on the heads were the same except for valves, 333882 until 78. I did learn a lot from your example, especially the cam grinds. Thanks.
Drifting
Joined: Mar 2004
Posts: 1,873
Likes: 1
From: Savannah Ga
Safety Car
Joined: Nov 2005
Posts: 3,961
Likes: 573
From: Lompoc, CA. Santa Barbara County
The L-82 springs were a little stiffer, but still almost junk. When I ordered my 79 the dealer could not understand why I would pay so much for only 30 additional horsepower. I said are you kidding? 2.02 heads, forged pistons,rods, and crank, four bolt block, more compression, and a big cam. I'm paying for potential.
First thing I did was to remove the catalytic converter and slap an edelbrock performer manifold on. What a difference getting some of that potential out.
Bee Jay
First thing I did was to remove the catalytic converter and slap an edelbrock performer manifold on. What a difference getting some of that potential out.
Bee Jay
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
Aluminum rocker covers
Tom,
Great info, it taught me some things I didn't know. However, I thought in '74 (at least) that the inlet manifold and rocker covers were aluminum on the L82, can you confirm?
Not too many people with this knowledge down in the Antipodes.
Regards from Down Under
aussiejohn
Great info, it taught me some things I didn't know. However, I thought in '74 (at least) that the inlet manifold and rocker covers were aluminum on the L82, can you confirm?
Not too many people with this knowledge down in the Antipodes.
Regards from Down Under
aussiejohn
Race Director
Joined: Apr 1999
Posts: 15,136
Likes: 477
From: NM
tom...
Racer
Joined: Mar 2007
Posts: 306
Likes: 0
From: New Hampshire
Tom, maybe 1978, my books do not go past 1977, The 1977 versions were the same, casting number34649. But your right, only difference would be weight. You'd gain more horsepower by placing an STP decal in your rear window! 
Le Mans Master
Joined: Mar 2004
Posts: 7,473
Likes: 1,495
From: Little Rock AR
Nearly everthing on an L-82 engine is different in some way. One of the only things that never changed during this time was the valve springs. There is only (1) valvespring for all the factory SBC engines. , L-48's, L82's, DZ 302 Z/28's, station wagons, you name it. They all had the same valvesprings. 
-Mark.
-Mark.
