Stock weight distribution for various body styles - can you improve balance w/out drastic mods?

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MRGTX

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Has anyone ever put their A-Body on corner weight scales? How did it come out?
How do the various incarnations of the A-Body stack up?

I have always heard that the coupe version of the A-body platform (Duster, Demon, Sport) had relatively good weight distribution and that all of the versions were decent for their era. Is that correct?

So most guys who aren't here for just repair/restore info are probably interested in improving chassis/suspension. What are the first things you'd recommend to make a significant difference in balance/weight distribution? What have you tried? What isn't worth the trouble?

The height of the center of gravity is a critical factor as well. Aside from lowering the car down, is there anything that can be done to affect that point?
 
Replace heavy cast iron heads and intake with aluminum parts. Replace cast iron exhaust manifolds with headers. Remove cast iron steering box and/or power steering and replace with aluminum steering box. Change to lightweight modern starter. Those are all pretty easy mods, removing lots of front end weight. Battery can pretty easily get moved into the trunk, although that adds to total weight, but puts most of it in the rear.
 
I have a nice healthy big block in my duster, i took 125 lbs off the engine with aluminum and lite weight parts. car is now 3100 lbs with full tank of gas without me in it.
 
Most A bodies were about 50/50 weight distribution front and rear, give or take 1% or 2%. That is with cast iron heads and intake. First thing was to put the battery in the trunk, Set height as low as you can within factory specs. Manual steering housing is aluminum.
 
On track-day,The best I could do on my streeter68 FB-Cuda SBM/A833/GVOD/8.75 was 1760/1512 f/r, total 3272; me not in it. That's 53.8% front bias, in track trim.
That was;
aluminum topend, wheels,and trans box. Battery in trunk.1/4 tank gas.
Removed; back seat(64),3"full-length dual-Exhaust(72),sway bar and skid plate(18),Heater(16),front bumper(30); the rear seat never went back in.
I left in; the P/S,P/B, and heavy 7-blade all-steel fan with it's T-clutch.
To hit 50/50 I would need to move 124 to the rear, or remove 248 from the front, or some combo. I know the P/S is heavy, but I'm keeping it.
Normal street weight with 1/2 tank of gas is 3550,(no rear seat), me not in it. And the bias changes to 52.5 front in street trim .
I used a balance-beam truck scale for before and after, so not sure about the accuracy; but the bias won't change much.
 
I would never have guessed these cars being so close to 50/50 .
It doesnt seem like headers weigh much less the stock manifolds. Maybe its an illusion.
 
I would never have guessed these cars being so close to 50/50

Most are not. Most V8 street combos are closer to 60/40 than to 50/50.

Easy front end diet:
Trunk mounted battery
Manual steering
No A/C
Lightweight Disk brakes and wheels.
Aluminum radiator


On my Swinger, I've gone so far as to swap in a 340lb, 300hp 3.6L Pentastar. It's not only a couple hundred pounds lighter than a 340, but 10" shorter and pushes the CG in further back. The cars not quite done yet but I will definitely be getting the corner weights as soon as I get a chance.
 
Great info, guys.
How do the different body styles compare relative to their distribution? I have to imagine that a 111” Dart will be distributed differently than a 108” Valiant or Duster.

While this is still great info, I guess I’ve done most of these things already; manual steering swap, aluminum radiator, aluminum intake, tubular headers, mini starter...still eyeing aluminum heads but that’s a relatively big investment (for me at least!).

Is there much weight to be saved with fiberglass body panels? How much does the rear seat weigh in these cars?

As for moving the battery to the trunk, I’ve always imagined moving it to the front of the trunk. In this case, the weight distribution may not be as valuable as reducing the polar moment of inertia when it comes to changing direction. Has anyone tried this? Would this be preferable to the usual right rear corner (where drag racers would put it)?

Speaking of the battery, is there weight to be saved with a smaller battery? I know AGM batteries are pricey but they could save a lot of weight and last a really long time. Are there other options?
 
As for moving the battery to the trunk, I’ve always imagined moving it to the front of the trunk. In this case, the weight distribution may not be as valuable as reducing the polar moment of inertia when it comes to changing direction.

I'd still say that improving the Front/Rear weight distribution is a higher priority. The Cg position is going to favor the front end and be too high unless you go to more drastic lengths to strip weight.

A +40lb ballast that is the battery needs to be put where it makes the most difference. Putting the battery in the rear passenger side of the trunk not only offsets the drivers weight but also adds additional advantage of the moment it creates about the rear axle to further improve Cg.
 
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I'd still say that improving the Front/Rear weight distribution is a higher priority. The Cg position is going to favor the front end and be too high unless you go to more drastic lengths to strip weight.

A +40lb ballast that is the battery needs to be put where it makes the most difference. Putting the battery in the rear drivers side of the trunk not only offsets the drivers weight but also adds additional advantage of the moment it creates about the rear axle to further improve Cg.

I hear what you’re saying...you mean rear passenger side though, right?
 
I would never have guessed these cars being so close to 50/50 .
It doesnt seem like headers weigh much less the stock manifolds. Maybe its an illusion.

Agree, never heard of any A body with 50/50 !
 
66 Barracuda 273 - 55.5% front, 44.5% rear
67 Barracuda 273 - 55% front, 45% rear
Other A bodies?
Not measured, from articles.
 
66 Barracuda 273 - 55.5% front, 44.5% rear
67 Barracuda 273 - 55% front, 45% rear
Other A bodies?
Not measured, from articles.
That's not even close to 50/50, if you actually weigh them, there not even that good. Don't trust some magazine article.
 
66 Barracuda 273 - 55.5% front, 44.5% rear
67 Barracuda 273 - 55% front, 45% rear
Other A bodies?
Not measured, from articles.

It’s surprising that the 67 would have better weight distribution. I always assumed that one benefit of that glorious rear glass on the ‘66 would be that it sits over the drive wheels.
 
It’s surprising that the 67 would have better weight distribution. I always assumed that one benefit of that glorious rear glass on the ‘66 would be that it sits over the drive wheels.
When I drop Demon off the rack I will use my race scales and get corner weight for each. I had not even thought about it as I was building a daily driver. It is clearly not stock tho. 6.1 Gen three with Hemi Denny K frame battery in trunk alum radiator etc. great question and got me thinking (no small feat)!
 
Is there much weight to be saved with fiberglass body panels?

Fenders most likely No.
I've looked into it and its a wash at best. Factory fenders just don't weigh that much. So the "lightweight" fiberglass fenders don't save much and typically suffer from poor fit and finish. The "HD" fiberglass have better fit and finish but weigh as much as oem steel.

A fiberglass Hood can take some weight off.
Your 5mph Front bumper and its brackets could be another area to lose weight.
 
I am pretty sure the console and rear fold down seat in my fastback add around 1100 lbs ! Luckily its in the middle...lol
 
The center of gravity of most American production cars is the back edge of the front seat when the seat is in the rearmost position . It is designed that way so the braking will be balanced and so the car won't kill you if you have 6 people in it and a trunk full of luggage . In my case I removed the power steering (heavy), power brakes , A/C compressor/condenser , 24lbs of undercoating , 318,904, 8 1/4 . Replaced with 383 , 727 , 9" With a 6pt roll bar and 5 gallons of Lizard Skin . I'm thinking I'm about 200 lbs heavier on the nose . which can be adjusted with weights in the trunk . "Raising the ride 1" puts 100 lbs of weight on the opposite corner ."
 
From what I have read moving the battery to the back is very important. I remember some article saying it can improve weight distribution up to 2%, not sure what car this was on.
It does kind of make sense as your not only removing ~40lb from the front your adding it to the rear of the car, which overall has a pretty big effect on balance.
 
That's not even close to 50/50, if you actually weigh them, there not even that good. Don't trust some magazine article.
The article was from Mechanix Illustrated from 1967. I trust them. Of course every configuration changes the weight distribution. 170 /6 with three on the tree and 7 14 rear, compared with 383, 727, 8 3/4. Obviously, the best is when you measure them.
 
It’s surprising that the 67 would have better weight distribution. I always assumed that one benefit of that glorious rear glass on the ‘66 would be that it sits over the drive wheels.

They said the big change to 67, was moving the front wheels forward which shifted the distribution slightly toward the rear.
 
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