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A-Body Body Parts Comparison : Steel vs Fiberglass Weight

16K views 22 replies 10 participants last post by  ChrisKD 
#1 ·
So in my endless battle to make my A-Bodies every bit as fast as i can, i figured i'd start researching Alternative Body Parts. Not because i want to shave time off them at the track, just because i want them to accelerate faster and run higher. I'm always happy to have one of my cars perform better.

On my '74 Duster i'm going to be converting it to a '71 Clone ('71 Clip & Tail, with matching '71 Bumpers). I know i'm going to save at least 30 pounds swapping the heavy '74 Bumpers for the lighter '71s But 30 will barely put a dent in my Car's Weight  :p

So does anybody know how much lighter the Fiberglass Fenders are when compared to the Stock Fenders? How about the Fiberglass Hood vs the Stock '71 Hood (with Scoop)

What else can i do to lighten the '74? (Without sacrificing my A/C, Power Steering & Sway Bars) I'm already running a set of Low Profile Heated-Power Bucket Seats (roughly 18 pounds per seat), No Padding under the Carpet, No Spare Tire, No Trunk Padding, No Bumper Jack, LD340 Aluminum Intake, 8-3/4" Rear (Which is roughly 60 pounds less than a 8-1/4"), Keystone Klassic Wheels (50/50 Aluminum & Steel, 1 pound less than the Rallyes, each).  All in All i've shaved about 350 pounds off the car without even intending to do so (as it sits right now, before i convert it to a '71 Clone)

Keep in mind my A-Bodies are Street Driven Cars, so Lexan Windows, No Interior, ect are not a legal option  :p The same questions will also apply to my '71 Demon which is going to be an all-out balls to the wall street car that may occasionally see the track. Both my '74 and the '71 have A/C, Power Steering and Front & Rear Sway Bars
 
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#2 ·
Keep in mind the "street weight" fiberglass panels are not much lighter than the normal steel panels and the "race weight" panels require a lot of internal structure and Dzus fasteners to support them and keep them from cracking.  The race weight panels are not intended to be used on the street and will quickly crumble from the abuse of street driving.  I considered going to fiberglass panels on my '72 Charger when I was street racing it and sort of pondering a One Lap of America run (not to mention a total lack of '72 Charger fenders in my area) but when I found out I would only save about 100 lbs from swapping the whole front clip to street weight fiberglass I trashed the idea.

Oh and no interior is a legal option as long as you have the safety stuff in.  For more lightening you can swap to some real racing wheels and shave a lot of weight but most other lightening modifications have some sort of drawback to them.  About the only things I can think of that are worth it is gutting the interior/swapping to light racing seats, swapping to manual steering and brakes and the racing wheels.  My old Cragar aluminum racing slots were lighter with the tires on them than the bare E.T. (similar to Crager SS) rims with no tires.
 
#3 ·
A few les Big Macks lardo........lol, no serriously 350 lbs. sounds pretty impressive. Hood hinges, in exchange for pins? I believe Corvette used plastic headlight bulbs, though I don't know about the 'round' configurations. Aluminum drive shaft? Tubular upper A Arms? Comes a point when $$'s really come into play, and your becoming a Don Quixote........For all the effort, if you have $ to play with, Indy makes some nice BB aluminum stuff.
 
#4 ·
Gohot said:
A few les Big Macks lardo........lol, no serriously 350 lbs. sounds pretty impressive. Hood hinges, in exchange for pins? I believe Corvette used plastic headlight bulbs, though I don't know about the 'round' configurations. Aluminum drive shaft? Tubular upper A Arms? Comes a point when $$'s really come into play, and your becoming a Don Quixote........For all the effort, if you have $ to play with, Indy makes some nice BB aluminum stuff.
I doubt the Big Macs and Quarter Pounders are contributing to my car's weight. Especially since i tip the scales at 134 pounds :eek: :p

The '74 is powered by a Small Block, But i am going to be lightening the 340 up a little more (Aftermarket Heads), Hopefully shave a little more weight off it. The swap from the Cast Iron 4BBL Intake to the LD340 Aluminum 4BBL Intake knocked about 35 pounds off the 340 alone (yes the Dual Plane Cast Iron 4BBL is Heavy :eek: )

For the Demon though, there's all kinds of Aluminum goodies out there for the 426 Hemi, Hell i could build a complete aluminum engine if i wanted to. And to anyone who's never worked on the 426 before, lemme tell you just one of the hemi heads weighs close to 2 LA Heads :eek: So every bit of aluminum parts there would make a huge difference ;D
 
#5 ·
Just 35? Not 40? I think the heads should shave off 60 lbs.

I concur on lose the hinges and go to pins. Still hold it on, can still tie it in, but cut weight while keeping strength elsewhere. Better work on upper body strength though for the steel hood.

I agree with Elwenil on that, to be honest the panels aren't terribly heavy anyway.

The later model A/C would help shave some weight off. With a Duster, you may as well pull the backseat but leave the mounts. If the day ever comes that you need it you could put it back in, but they aren't that much good anyway.

By the way, the '71 front clip is a good swap to save weight. The '74 is heavier due to stricter safety standards that nobody cares about anymore, same on the rear. You may cut 200-300 lbs off it with that. Swapping '71 doors on would save weight too. The obvious parts aren't what is heavy, the inner structures and mounting for the '74 stuff is much heavier than for the '70. Yeah, that does mean it is safer but...

The million dollar question: where are you at right now?
 
#6 ·
85 Royal SE Prospector said:
Just 35? Not 40? I think the heads should shave off 60 lbs.

I concur on lose the hinges and go to pins. Still hold it on, can still tie it in, but cut weight while keeping strength elsewhere. Better work on upper body strength though for the steel hood.

I agree with Elwenil on that, to be honest the panels aren't terribly heavy anyway.

The later model A/C would help shave some weight off. With a Duster, you may as well pull the backseat but leave the mounts. If the day ever comes that you need it you could put it back in, but they aren't that much good anyway.

By the way, the '71 front clip is a good swap to save weight. The '74 is heavier due to stricter safety standards that nobody cares about anymore, same on the rear. You may cut 200-300 lbs off it with that. Swapping '71 doors on would save weight too. The obvious parts aren't what is heavy, the inner structures and mounting for the '74 stuff is much heavier than for the '70. Yeah, that does mean it is safer but...

The million dollar question: where are you at right now?
3,015 with me in the Driver's Seat, full tank of fuel and complete interior.

Agreed on the back seat... I've tried doing 'stuff' back there, it doesn't work out so well, especially at 5'11" :p
 
#8 ·
gmule said:
Honestly I would just add 100 shot to it and save the aggravation
It already has a 150 shot w/ a 10lb tank :p Don't have it wired up at the moment though. The Tank, Lines, Nozzles, Controller, Wiring, ect are installed in the car, but i don't have the wiring hooked up.

And no i don't have it rigged to some "Fast & Furious" "NAWS" Buttons ::) :p It's set to activate via throttle position above "x" rpms (adjustable through the controller)

Currently (without any power adders) it's around 600hp, aiming for 1,000+ (With the help of a Supercharger)
 
#9 ·
Power adders are ok.....but.....

Weight savings never need to be refilled.
Better braking/handling.
Less weight....less stress on drivetrain.

Combine less weight with moving weight for lower center of gravity and traction........
 
#10 ·
dyslexic teddybear said:
Power adders are ok.....but.....

Weight savings never need to be refilled.
Better braking/handling.
Less weight....less stress on drivetrain.

Combine less weight with moving weight for lower center of gravity and traction........
I'm part way there on the better braking/handling. Front & Rear Sway Bars. This winter it gets Rear Disc Brakes and a set of 1.03" Hotchkis Torsion Bars. Not sure, but the Rear Disc Brake Conversion might shave a little bit of weight off the car too (weight of the calipers, rotors & ceramic pads vs the weight of the drums, backing plates, shoes, and mounting hardware)

Good point on moving/relocating weight, it could benefit from relocating the battery to the trunk. Get a little bit of weight off the front wheels and focus it over the rear axle. I'd yank the gloveboxes out (dash and center console) but i actually use those ;D

Anybody have a weight comparison of a 727 (with Converter & Flexplate) vs a 18-Spline Hemi A833 with LA Bellhousing, Flywheel, Pressure Plate, Clutch Disc, ect? I'm pretty sure there's alot of weight savings to be found in that swap, and i just so happen to have a few 18-spline A833's sitting in the garage ;D And i'm working at building replicas of the 4-Speed Pedals (based on one of the two sets of the "worth their weight in gold" a-body 4-speed pedals that i have on hand)
 
#11 ·
Well the old A-body cudas and darts ,
Used FBG nose , doors , decklid, lexan glass, no window regulators , A100 seats, no rear seat , no sway bars , and no heat or ac.
But you want some comfort !
That adds to problem .
One thing you could do to improve launch is disconnect sway bars ( if drag racing ).
Six cylinder torsion bars were the normal thing too on drag cars,
Battery relocation smart move , make sure to use sealed ,vented to outside box.
Try to find the Liberty style 833 trans housing , its aluminum, if running 4 speed.
Good pinion snubber helps , not traction bars ( they wipe out wheelbearings, I don't know why but they do ) .
there are other ways but without a gutting its not happening , and all those fbg parts on street car could be potentially dangerous in a accident situation.
 
#12 ·
ChrisKD said:
Anybody have a weight comparison of a 727 (with Converter & Flexplate) vs a 18-Spline Hemi A833 with LA Bellhousing, Flywheel, Pressure Plate, Clutch Disc, ect? I'm pretty sure there's alot of weight savings to be found in that swap, and i just so happen to have a few 18-spline A833's sitting in the garage ;D And i'm working at building replicas of the 4-Speed Pedals (based on one of the two sets of the "worth their weight in gold" a-body 4-speed pedals that i have on hand)
Being a small block you have lots of options.

904 (cut weight, improve transfer), 833 aluminum (cut some weight off the 4 speed), or 5 speed/OD with ease.
 
#14 ·
Eh, anymore with the price of aluminum being down, even the aluminum racing radiators are cheap enough to be affordable replacements for just about anything.
 
#15 ·
tried to find the article on 70's feather light ( i think ) darts. Came with /6 and 318's, but also had factory aluminum hoods, and other means of saving weight for fuel savings. most people dont care about these cars because they weren't performance cars.
 
#17 ·
Here's your info on the lite pkg. ,

New Dart Lite Competes For Compact Economy Crown
DETROIT -- Dodge is introducing a liteweight contender for the compact car economy crown.
Called the Dart Lite, the 1976 Dart Sport with the fuel economy package weighs in more than 150 pounds lighter than the conventional version of the popular compact.

Dart is available for 1976 in low line versions of the coupe, two-door hardtop and four-door sedan, and a high-line version of the two-door hardtop. A series of merchandising packages are available so that the motorist can tailor his Dart to meet his motoring needs.

"The Dart is one of the most successful compact cars ever introduced in the American automobile marketplace," according to R. D. McLaughlin, vice president of Chrysler's Automotive Sales Division. "It enjoys a strong owner loyalty and is a car that has established a reputation for reliability and value.

"In a price-conscious market, Dart will have an advantage. The car has more than a decade of building a strong reputation for extra value as a new car purchase and good value at resale. These are the reasons why we will continue to market the Dart while introducing the new compact Aspen," he added.

Weight saving in the Dart Lite economy package is accomplished by use of aluminum components. The 225 six cylinder engine, the only powerplant available with the package, is equipped with an aluminum intake manifold.

Bumper reinforcements are aluminum instead of steel and the hood and trunk lid inner panels also are fabricated from aluminum instead of steel.

In addition to the lightweight manifold, the engine block has been modified to lessen the weight. A dual biscuit catalyst is utilized and a new, larger exhaust system is a part of the Lite package.

The Lite is equipped with a 2.94:1 rear axle when the car is ordered with a three or four-speed manual transmission. A three-speed column shift is standard and three-on-the-floor and Overdrive-4 manual transmissions are optional. A 2.76:1 rear axle is standard on Lites ordered with automatic transmissions.

Dodge's Overdrive-4 manual transmission has a 0.73:1 final drive ratio which allows cruising at highway speeds with minimum engine revolutions. When the Overdrive-4 transmission is ordered with the Lite package, the transmission case is made of aluminum.

In addition to the 225 six, the Dart line includes the 318 cubic-inch V-8 and 360 cubic-inch four barrel V-8. The 360 is available only in the performance oriented version of the Dart Sport.

The various merchandising packages available for the four 1976 Dart models allow the buyer to outfit his car in trim levels ranging from the high line Custom package to the premium line Special Edition trim.

Rear axle ratios, vital to economical fuel usage or performance -- whichever is preferred -- are available in a wide selection. A 2.45:1 rear axle is mated with the Federal 318 V-8, while the six has a 2.76 standard rear axle. The standard ratio for the 360 four barrel V-8 is a 2.94:1 rear gear. Also available is a 3.21 rear axle option.


--------------------------------------------------------------------------------
Return to the List of Press Releases
Return to the Dodge Dart Page


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Maintained by Joseph Newhouse / E-mail Joseph Newhouse
 
#19 ·
You might be at your limit here for a daily driver. If you want to chop off weight from the body, keep in mind that you may need a roll cage to protect your life, which is going to add weight. At this point the best you could hope for is to shave every ounce of weight and you're gonna have to determine whats important to you.

The race fiberglass is thin stuff, but you could attach a fiberglass hood to the steel frame (with lots of "lightning" holes drilled into it) to stiffen it up. At this point, even a "thick" 'glass hood which saves you a few ounces might be worth it to you. Perhaps you can find 'glass bumpers.

There is a lot of weight in the interior, the problem is, getting rid of the insulation will result in a hotter ride in the summer and a colder ride in the winter. The entire dash could be eliminated and a simple set of aftermarket gauges will save weight. .

Ed

 
#20 ·
RXT said:
You might be at your limit here for a daily driver. If you want to chop off weight from the body, keep in mind that you may need a roll cage to protect your life, which is going to add weight. At this point the best you could hope for is to shave every ounce of weight and you're gonna have to determine whats important to you.

The race fiberglass is thin stuff, but you could attach a fiberglass hood to the steel frame (with lots of "lightning" holes drilled into it) to stiffen it up. At this point, even a "thick" 'glass hood which saves you a few ounces might be worth it to you. Perhaps you can find 'glass bumpers.

There is a lot of weight in the interior, the problem is, getting rid of the insulation will result in a hotter ride in the summer and a colder ride in the winter. The entire dash could be eliminated and a simple set of aftermarket gauges will save weight. .

Ed
Daily Driver is a bit of a loose term. I put 850 Miles on the Car last year (driving it from April to October) In the winter (and on rainy days) it gets parked, I may be stupid but i don't have a death wish :p Drove it in the rain once, couldn't keep it locked to the road. Turned around, took it home and drove my truck instead :p (that was also the day that the windshield wipers in the car quit :p )

I can feel the heat of the exhaust through the floor with no insulation, but i can live with that.The car has factory A/C, one feature that will always stay, because driving a all-vinyle/all-black interior in the summer is brutal without a/c. It has thin Automotive Carpet in it (no insulation/padding), just enough to cover the floor so the inside looks nice/complete (no carpet under the console, bucket seats or rear seat though)
 
#21 ·
Had that problem with our Duster.  Got caught in the rain because I had to stop for fuel since the 8 gallon fuel cell we were running didn't have enough to make it home.  Tried to pull out at a stop light on a hill and it just sat there.  Tried to hold the brake and ease into it and still nothing but spinning.  With the 4.56s and the 383, the Mickeys didn't have much of a chance with the wet road and the incline.  I ended up sliding backward into the truck behind me.  Luckily it was a friend of mine who was laughing his ass off at me trying to make it over the hump in the intersection and he just shoved me on over it.  I think the Duster's bumper still has a little black paint on it from his pipe bumper.


Which brings me to another point, you can also limit the fuel you run in it.  Gas weighs a lot when you get enough of it.  I don't recommend going as low as 8 gal though.  With a 383 under the hood with a Tarantula and 750 double pumper on top we stopped for fuel about 6 times a night when we raced, but we were running what we had and the Duster's stock tank was shot, literally.  ;D
 
#22 ·
ChrisKD said:
(that was also the day that the windshield wipers in the car quit :p )
Well you can get rid of the windshield wipers and motor since they don't work, should save a few ounces there :)

Ed
 
#23 ·
RXT said:
Well you can get rid of the windshield wipers and motor since they don't work, should save a few ounces there :)

Ed
It was the bushings, i replaced them. Need em for the car to be street legal.
 
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