'73 L82 heaver then L48, why?
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From: NM
'73 L82 heaver then L48, why?
Anyone know why the 1973 L82 is 42 pounds heavier then the base L48? The harmonic damper on the L82 is larger which would add a couple of pounds but not 42. Both used the A.I.R. emission system. Both had iron intake. So what would be the difference? (This weight difference is per some GM documentation that I just posted to my web site, The '73 Spot, just go to factory bulletins, then select page 7 under '73 Passagner Car Registration Data.)
tom...
tom...
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Re: '73 L82 heaver then L48, why? (Tom73)
Probably the "extra" bolts for the "four-bolt" mains and the cast finned L-82 valve covers were probably heavier than the L-48 thin stamped steel ones. :lol:
Also when GM weighed these cars, was the L-48 car loaded with A/C, power windows, power brakes,etc compared to the L-82 car? Maybe the L-82 car had more gasoline in it, which weighs about 8lbs per gallon :confused:
Also when GM weighed these cars, was the L-48 car loaded with A/C, power windows, power brakes,etc compared to the L-82 car? Maybe the L-82 car had more gasoline in it, which weighs about 8lbs per gallon :confused:
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From: NM
Re: '73 L82 heaver then L48, why? (Paul Borowski)
Also when GM weighed these cars, was the L-48 car loaded with A/C, power windows, power brakes,etc compared to the L-82 car? Maybe the L-82 car had more gasoline in it, which weighs about 8lbs per gallon
tom...
[Modified by Tom73, 11:49 AM 3/4/2002]
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Re: '73 L82 heaver then L48, why? (Tom73)
This may or may not be relevant to your question. I don't know exactly when GM started doing this with automatic Corvettes but sometime in the 1970s the L-48 cars got TH350s and L-82s got TH400s. The TH400 trannys are heavier.
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From: NM
Re: '73 L82 heaver then L48, why? (The Dude)
All 73s had the TH400. But this is comparing like cars. A no option L48 4-speed with a no option L82 4-speed. Check out this page to see what I am talking about: http://www.corvetteforum.net/c3/vette73/reg7.jpg
It is interesting, A/C adds 94 lbs, power brakes 10 lbs, power steering 26 lbs, power windows 7 lbs, L48/auto 56 lbs, L82/auto 96 lbs, 454/4-speed 211 lbs, and 454/auto 265 lbs.
tom...
[Modified by Tom73, 1:52 PM 3/4/2002]
It is interesting, A/C adds 94 lbs, power brakes 10 lbs, power steering 26 lbs, power windows 7 lbs, L48/auto 56 lbs, L82/auto 96 lbs, 454/4-speed 211 lbs, and 454/auto 265 lbs.
tom...
[Modified by Tom73, 1:52 PM 3/4/2002]
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Re: '73 L82 heaver then L48, why? (Tom73)
In 78 the L-82 had a dressed weight of 640.7 lbs while the L-48 was 622.4 lbs - of course the L-82 in 78 had an alum intake not iron. The Pistons are lighter but the rods are significantly heavier 20.80 oz vs 13.70 oz (ea). The crank, main caps and the additional bolts add weight.
Are both of these cars with the same suspension items?
The rear leaf on a gymkana is heavier due to thicker (but fewer) leafs - front and rear sway bars maybe?
exact same tires?- even mounted on the same wheels - wider tires weigh more.
Gear ratio? do all rear gears weigh the same? do the lower (higher numberically) gears have thicker rings (or thinner?)
I'm just grasping for straws now.....
:crazy:
Are both of these cars with the same suspension items?
The rear leaf on a gymkana is heavier due to thicker (but fewer) leafs - front and rear sway bars maybe?
exact same tires?- even mounted on the same wheels - wider tires weigh more.
Gear ratio? do all rear gears weigh the same? do the lower (higher numberically) gears have thicker rings (or thinner?)
I'm just grasping for straws now.....
:crazy:
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Re: '73 L82 heaver then L48, why? (Tom73)
Of the 42 pounds 36 was on the front springs and 6 was on the rear springs.
Engine differences L-48 vs L-82; Crankshaft:cast iron vs forged steel, a forging is more dense and thus heavy than a casting & steel is more dense than iron: Pistons; cast aluminum vs extruded aluminum, the cast piston is heavier than the extruded one - 21.17 oz vs 20.40 oz: Crankshaft is held in by 15 bolts vs 21 bolts, extra bolts-extra weight, but I'm certain that the bearing caps for the 4 bolt were larger to accomadate the extra width for the 2 extra bolts. Bearing caps could have been steel vs iron - not certain about this, but a guess. The larger valves made of alloy steel added some weight. Rear end ratio was 3.36:1 for the L-48 vs 3.55:1 for the L-82, maybe extra teeth in the gears - more teeth more weight. These are the only differences I see in the GM specification package for 1973.
Roger
Engine differences L-48 vs L-82; Crankshaft:cast iron vs forged steel, a forging is more dense and thus heavy than a casting & steel is more dense than iron: Pistons; cast aluminum vs extruded aluminum, the cast piston is heavier than the extruded one - 21.17 oz vs 20.40 oz: Crankshaft is held in by 15 bolts vs 21 bolts, extra bolts-extra weight, but I'm certain that the bearing caps for the 4 bolt were larger to accomadate the extra width for the 2 extra bolts. Bearing caps could have been steel vs iron - not certain about this, but a guess. The larger valves made of alloy steel added some weight. Rear end ratio was 3.36:1 for the L-48 vs 3.55:1 for the L-82, maybe extra teeth in the gears - more teeth more weight. These are the only differences I see in the GM specification package for 1973.
Roger
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From: NM
Re: '73 L82 heaver then L48, why? (RMS73)
Crankshaft is held in by 15 bolts vs 21 bolts, extra bolts-extra weight,
tom...
[Modified by Tom73, 7:39 PM 3/4/2002]