I don't know your post set awhile no one answered but I did first screw you.

 

I say: Make the car lighter AND make the engine more powerful. Don't forget about gearing either, but that's its own area. (10:1 in first gear should do the trick)

When I was a little kid, my mom worked as a bookkeeper, and when she was teaching me how to balance a checkbook, she said, "Take care of the pennies, and the dollars will take care of themselves." It's the same with weight reduction. Take care of the ounces and the pounds will take care of themselves. What that means is, a 5 lb. reduction in weight should not be looked at out of context, so to speak. We've all heard people say, "It all adds up." Well, it does. if you do 20 things that reduce weight by 5 lbs., that adds up to 100 lbs., which is a significant amount of weight. A 225/70-15 tire weighs a little bit less than a 255/60-15 tire. And that's spinning un-sprung weight. You would be amazed at how much of your braking force does nothing to slow down the mass of the car. Most of it goes toward slowing down the spinning mass of the wheel and tire.

The thing about weight reduction is that you quickly run out of things that you can just remove from the car and do without. Most of the pieces of a car kinda need to be there for the car to work. Most of the easily removed and discarded things on a car are already pretty light anyway. So, we are eventually faced with replacing heavy parts with lighter parts, and this is where things can start to get expensive. On our C3 Corvettes, this mainly involves removing things made of cast iron, brass, copper, etc. and replacing them with things made of aluminum.

A 2800 lb. Corvette seems like a stretch to me, my goal with my 1980 Corvette is to get it down under 3000 lbs. with a full tank of gas, spare tire and jack stowed. I'm an enthusiast, not a fanatic!

Scotty

 

Of course weight matters. So does HP.

My friend and I did an experiment where we took the exact same untouched 580 HP BBC engine out of a pretty fast 10.6 sec 70 Chevelle, that weighed 4000lbs, and dropped it into a 220" rail Super Comp dragster, that weighed only 1600lbs. The ET dropped like mad. That old engine then went 7.8s at around 185 or so, and 0-60 in 1.5sec. Our 2400 lb "diet" was worth 2.8 seconds. That's 86 lbs per tenth.

The power to weight ratio dropped from 6.9 lbs to 2.8 lbs per HP.

But a small change is just that...small. It would take either 86 less lbs or 18 more HP to make that Chevelle 0.1 sec faster. Less than that and you'll never notice it.

 

Stretch maybe, but entirely possible. Just depends on your ambition. My '69 is 2700#. It's a non-A/C car, and this weight is without the spare tire (won't fit with the big quiet mufflers I have), and about three or four gallons of gas in it when I had it weighed. Full factory interior, carpet, sound deadener, t&t, p/s, pb, carpet, heater, radio). Everything under the bodywork that can be replaced with aluminum (and can accomodate a coat of semi-gloss black for a more stock look) has been done. It won't pass an NCRS inspection, but at track days the car rarely gets a second glance until after the first track session.

High horsepower is an amusing thing, but it takes more fuel (adding vehicle weight), and tends to break things, which require stronger (and usually heavier parts), which then require bigger brakes (which are always heavier) to stop the car. As a wise man said, weight begets weight.

I agree with you regarding watching the ounces. I weigh every part that comes off or goes on this car. The ounces (up or down) add up.

 

I've got a legit recipe for a sub-2900lb C3, using ONLY OEM parts (except exhaust and hood). Its possible. I might try and go that route, just to prove it, but being that i'm broke, i'll likely stray and snap up whatever lightweight aftermarket i can get my hands on. These can be 2500lb cars without being clapped out.

I've always liked your car. I wont be using a big block, as i plan to race mine, AND daily drive it (4 seasons), and in the land ov $8/gallon gas. Big block is not an option. So i'm gonna go modern, and keep it well under 350cid. 350-400rwhp should be more than enough to move a 2800lb (or lighter) car. If i need to go faster than that, i'll actually buy some fancy light parts, and actually build an engine.

I'd have started already on my 73, but its an automatic... and it NEEDS a standard. I'm on the fence on whether i should do the swap, or just start with a different (and older) car.

 

there is one argument for a borg T5. it is the lightest 5 speed. least expensive too. (there is a downside. your wallet will still be heavy.)

 

Weight loss is important in performance , I had a 3/4 tank of fuel and a extra large pizza with dbl cheese , dbl pep and onions on the Tee top .. Brakes alone saved 88 pounds ...

 

Oh do tell...

 

There are more ways to save weight then not. Targa top is 12 lbs lighter then the t-Tops. My headlights saved 28 lbs , Brakes saved 88 Coil overs front saved a few. Alum Heads / WP , Full Ac Delete . . Hood was 15 lbs , Made a Chrome molly cross member for trans , Front Tubular control arms 12 lbs .. 4 Link saved a few ..If I remember more ill post it up .. All weights are my memory and i am on the light side of most of it.

 

8 lbs. here, 12 lbs. there, 15 lbs. somewhere else.....if you're not careful, you're gonna end up having to tie a big rock to your 'vette to keep the wind from blowing it away!

Scotty

 

Hey, what was that crossmember worth? One ov the first things i plan to do once everything is daily-driving, is build a real exhaust. For that i'm going to need a new crossmember. Planned to fab one out ov aluminum, or something light. Curious as to how much weight i would save.

Oh, and how much do you have to spend on brakes to save 88lbs? I know the Wilwood calipers save around 40-45.

 

Got rid of the brakes, huh.........well, they'd only slow you down anyway.

 

I did not weight it b/c the trans would not work with it so I used chrome moley tubing , which weight nothing practically .. And I could drop another 100 lbs if I go with a power glide and dump the 4L80e .. Which added weight over the 350 by about 75 lb

 

Was curious what the chromoly crossmember weighed actually. I'm sure someone here has weighed a factory crossmember.

As for the powerglide... thats akin to using bias-ply skinnies and 15x4" Weld Draglites on all four corners. Yeah, you'll save a TON... but how fun would that be?

 

Thats a very bad comparison . For drag racing the P/G is 10 times better then a 4L80e . Yet the 4L80e is better for mixed use on the street and strip. And now that I own a C8. I am debating with myself to ditch the 4L80e . . . Go to the P/G and wire up my 150 shot of Nitrous ....

 

I have a 70 454 vert and i feel it is very heavy but my racing days are over. Ive raced a lot of cars and had the most fun road racing an early 911/930 in a very competitive West Coast group. weight savings was very important and not just for top speed. weight distribution, center of gravity and unsprung weight were all big factors. nothing more fun than great steering and braking with a lightweight car.
think about moving center of gravity lower, reduce weight of brakes and wheels, lower the drivers seating position etc. with high gas prices you dont want to overcome everything with horsepower to achieve your goals and have a fun ride. As long as youre not NCRS restricted have fun with the mods but dont go crazy on stripping your car at the expense of having something uncomfortable.

 

Yeah, i get that, but that is literally ALL a powerglide can do. Had a Buick with one once. Horrific. Also, i dont drag race.

 

Agreed. There are weight-loss piranhas... that hack and holesaw everything, use lexan, use a 'race' dash, destroy 3/4 ov the car, etc... 100% clapped out. And then there are weight loss wizards. Some are so good you dont even know you're talking to one. Often starts with 'Man... that car moves a whole helluva lot faster than it should...' You know the type... if he breaks down in the pits, he wont let anyone else help him push the car...

My last real car was a 72 Charger SE, 440, set up for road race. Daily drove it for 5 years. The ONLY lightweight part on that car was the intake manifold... everything else, including the wheels (the BIG wheels... 15x8 heavy steelies and 295/50's on all 4)... was steel. Thing weighed under 3600lbs empty. Might not sound light to a Corvette guy, but thats a 4000lb car with a 440 all day long. The hemi's could weigh 4200lbs. Total budget, including the car, was $6000. If i actually LIKED that car... and could stand working on it, it'd have weighed 3300lbs.

Less weight makes EVERYTHING better.

 

Figure on the difference on iron and aluminum being about 2 1/2. One BB aluminum head weights 42 pounds. (Brodix). So Ihis indicates one iron BB head is about 100.5 pounds. Does this calculation look about right for a BB iron head? Still, getting rid of BB iron heads is a real plus for weight off the nose..

 

One pair of assembled aluminum BBC heads is 56# lighter than the iron versions. Not as much of a difference as the internet myth, which seems to grow over time.
These were scale weighed. The Scale accuracy is in second column. Weights vary between shipping weight, assembled weight and bare also. I have acquired a 69 Camaro weight database and am adding C3 Corvette components to it. So that we C3 owners have access to facts, not heresay. I posted it in an earlier post in this thread.
Still 72# for each iron one is pretty hefty! 45# each for AL is much more mamageable.
SBC can also save 50# with AL heads.
Who would have thought a BBC has 15# of valves and springs?