Sean81

I have recently acquired a pretty ratty '81 with a non-original 350 of unknown origin. I'm going to make a semi-presentable resto-rod out of it eventually, but I would also love to have a track day car. I'm just wondering if this is a realistic goal for this particular car. I'm not really into drag racing, so my primary concern is handling and braking. Does anyone out there have a street-legal C3 that they use for autocrossing or track days? If so, do you find it to be an enjoyable platform for those events, or would you recommend a newer car?

FKING1

There are 6 or so C3's from 68 to 79 that regularly autocross in the Corvette Club of Michigan. Several are top runners and all do fairly well. Couple are stock and others upgraded suspension.Mine has a 383 stroker.
Be prepared to spend some $$ to get a decent runner.

midnight02

I'm interested in doing the same thing. I've always wanted to get a '69 coupe and make it an auto-x street legal car but I never knew if they were a good platform. I fully understand it will cost quite a bit to upgrade parts to handle tracking it.

vetteguy22

I see a fair amount of C3's on the auto cross course. I am in the process of building a street legal 1970 for the road race course.
Always love to see the C3's on the road, weather it's the streets, auto cross or road course.

gkull

IMO - as an Auto-X car the C-3 vette is at a DISADVANTAGE because of the long nose and wheel base. Poor steering, class it competes in.

It is cheaper to just buy an X roller or turn key race car for track use.

You can find C-5 and now C-6 track cars for Under $20,000 with a trailer

Track use I mean road racing tracks

81pilot

Wrong on all counts They make fine AX cars. Steering is fine if it is rebuilt and tight. Wheel base is only a Dis-A on a tighter than normal course. If it started life as a Gymkhana car even better...As far as cheaper to buy one....you must live on a different planet than I do....especially a C5 or 6 with a trailer.....not around my part of the country at least. Mine does fine on a course, it handles well and places ok. It is still a work in progress, but won't break the bank when done. I will even have it track ready for Hallet with nowhere near the money some pour into thier cars. To make a driver/track car, is not that hard. If you plan to win every race or be competitive every time out, they will nickle and dime you into bancruptcy.

birdsmith

I spent several years racing with VARA in a '67 Mustang during the 90's (either in B Production or A Sedan) and there were quite a few C2 Corvettes running with me. Some were faster, some were not, depending on the expertise and bank account of the individual.

For some reason C3's were pretty rare, but for my money a C2 is a better race car because there is more room under the hood to work. Other than that it's pretty much the same car as a C3. IMO, when raced against Mustangs of the same vintage, the basic C3 platform suffers from a few disadvantages...

(1) It's HEAVY. GM put a lot of metal in the frame to try and stiffen it, and if you look at the basic shape of the frame it is inherently flexible. In spite of its heft, it's still a pretty flexible piece, and the body does very little to add stiffness to the overall structure of the car. It's basically [very pretty] dead weight. A Mustang, on the other hand, is a very torsionally stiff piece of structure AND it's 800 lbs. lighter than a C3 Vette. Do a little research on the kinds of things 60's Vette guru Dick Guldstrand did to lighten his. Rumor has it his frames were like Swiss cheese...

(2) Rear suspension geometry can be a bit sketchy. the 'three-link' trailing arm design causes 'toe-steer'; a condition whereby when the car 'heels-over' into a turn the deflection of the outside tire causes it to literally steer outward, giving the driver the rather unnerving sensation of the car not wanting to go where he's pointing it. This can be corrected somewhat by running a rock-hard rear spring and super-stiff swaybar, which is rather common practice in production-based race cars anyway (I was running 700 lb. springs in the front of my Mustang...).

(3) As mentioned in (1), C2/C3 Vette frames are rather flexible. Not a good thing for suspension tuning, especially in a car with a rear suspension design that demands super-stiff springing. And Chevrolet KNEW this, that's why the Grand Sport frames were a lot more like the frame of a 427 Cobra than anything that rolled off of a GM production line. All of the real racers back in the day (and today, for that matter) reinforce the original frame by triangulating the front and rear of the stock frame into the main rollover hoop. This magically stiffens the whole unit to the point where you can actually run 700-lb. spring rates without the worry of the car twisting like a noodle when cornering. I have seen the odd C2/C3 from behind in this configuration, and when driven correctly they can be a fearsome proposition indeed.

If you didn't already know this, the keys to making ANY car faster are light weight, lots of power, and a chassis that does what the driver is telling it to do by not moving in directions that it isn't supposed to, and it is no different with a C3 Vette. There ARE some very good ingredients to begin with in many old neglected C3's...

Low initial cost
4-wheel independent suspension
4-wheel disc brakes
V8 power

...but to hone all those properties into a truly fast race car, you generally need to-

Take out weight (wherever possible)
Stiffen the structure
Stiffen the suspension
Add power.

I've gotten some disrespect on these pages for my opinions in the past, but I HAVE done some racing in the past, even to the point of being semi-competitive, and have learned these things as universal principles. Remember, a Corvette doesn't know it's a Corvette. It's just a bunch of parts.

gkull

Just look into the back of SCCA magazine. All kinds of race cars for sale.

I don't believe that a C-3 is a good A-X base. I've been at it in my C-3 with auto-X from the early 80's and shifted over to road racing super bikes. In the 90's I tried my c-3 in BSP,BP We had to compete with later Vettes with ABS. Even with lots of mods and slicks any SWB or AWD would smoke your C-3 AX times. I also was turned off by spending a whole day and getting under 3 total minutes of track time. Usually one practise and two runs for time. I said **** on AX and just started running at the local tracks. I spent alot of money competing. It reaffirmed the conclusion that any smart person would come to. That you can't take a street car and make it into a race car It is a waste of time and money. That is why I said buy a car that someone else already put $40-$50,000 into that is capable of really fast road racing lap times.

69427

I take my car to the track every chance I get. Several of the above suggestions are definitely worth considering. (Less weight, more power, and better brakes and tires.) The later Corvettes have a crapload of tire under the fenders, which is a serious advantage over a C3 (unless you flare the fenders). I got tired of bandaiding the stock C3 suspension geometry so I finally just put a C4 suspension under it. That's not an option for everyone, but I enjoyed the technical challenge, and really enjoy how much easier and predictable the car is to drive.

I agree with George on autocrossing. Too much standing around, and too little track time. Track days or test & tune days are much cheaper (okay, less expensive) on a dollar per mile basis compared to autocrossing.

gkull

The mods to make a c-3 rear end bullet proof enough to actually race a Vette almost makes it cost prohibitively expensive. I probably have $8000 in the rearend to the wheels just to cure oversteer. Not even including the fender flares and paint jobs.

http://www.tomsdifferentials.com/201...Pages14-23.pdf



Hey 69427 this summer I bought a Stihl ms461 chain saw with a 28 inch bar for falling and bucking fire wood

SuperBuickGuy

I use my C3 for exactly what you're looking to do.... and there are plenty of C4, 5 and 6 drivers have stopped giving me grief about my choice of cars.

Yes, the IRS is problematic; but if you have any kind of mechanical skill you can either do the C4 rear or look up Guldstrand suspensions

Best part of all

I have have maybe 10k in my Corvette and it does run with ones that cost 5x more.... do I win? yes, do I lose, affirmative.... but I have a lot of fun with the car and that's the entire point. If I wanted a race car, I'd buy one; but I like having a Corvette that is fast, fun, and light

Lt1er

Back to this original question. You can race anything...... even a VW So it comes down to if you want fast time of the day in your class or just out enjoying your car. Just from what I have read here, you seem to have the competetive guys who have more money in their engine alone than guys on the low end like SuperBuickGuy,I have have maybe 10k in my Corvette I don't even think $10K covers GKULL's one season of slicks and entry fees.

So my advice is add up the cost to mod your 81 compared to buying an already setup car. The C-3 is a classic and I like my old 71

3JsVette

Do you want to auto x or track day? Do you want to have fun or win? How much do you want to spend?

Take a look at this link and play the video. Consider the car, the mods, the competition, and most important the driver.
http://www.corvetteblogger.com/2012/...ppg-nationals/

Sean81

Thanks for all the input, guys. I'm brand new to the Corvette scene, and it's great to hear from folks with some experience.

I have a long way to go on this project and a very tight budget, so I guess I'll just take it one step at a time. Right now the car is pretty scary to drive even at highway speeds--pulls unpredictably under acceleration and braking. I have some track time in import stuff (Miata, VW GTI) that felt much more promising initially. I'm just getting a bit too old for the "boy racer" stuff and want a car that will hold it's value. Once I get this old Vette into safe driving condition, I'll take it up into the mountains and see how it feels.

redvetracr

...

gkull

It is not really worded right, so it was of nice of you to bring it up. As I had problems I replaced everything with better parts. The richmond gear, billet main caps, case machining, $950 dollar toms posi. $550 yokes. The $2000 1350 half shafts and billet stub axles. HD trailing arms with 1/2 inch studs. adapter and wheels to add 6 inches of rear track width.

I would say that careful posi setup, rear spring selection, 6 inches of additional rear track width, 12 inch rear wheel size with 335 width tires all add to how well the rear end sticks. Nearly solid diff. crossmember and snubber setup. Then getting a higher weight bias on the rear. Then time to figure out the rear alignment settings. It also helped working at a shop that maintains winning historic racing cars

81pilot

You will notice real quick on this forum that there are folks, that regardless what you say, it will end up looking like you need to own the Taj Majhol to be able to afford anything, and that is just plain nonsense. The first time I ran mine at Hallet I was hooked. From there I was determined to make sure, 1. It was safe(R), or safer to continue 2. I could be resonably sure I could push it without breaking everytime 3. I wanted to be as competitive as I could be within my budget but if not, at the very least have fun. I can do all of that with the street car I have and am making a bit faster. I no illusions of ever having nor building a race car, BTDTHTTS. I used to drag race a lot of cars, I built many "street cars" and made them completely unstreetable quickly, but they were super fast going straight. This one I plan over time to do things as I can afford that may or may not lower lap times, but I can tell you right now, it is already a blast to drive, the best? Maybe not, the fastest? Not most days I am sure, do I like it? You bet I do, I like the way a C3 feels, handles and just plain "is". And I can't afford to go buy a race car, and I darn sure don't want to put a C4 suspension under it or any other non C3 thing to make it drastically better. So I will be content to tighten it up, add a few more ponies when the motor I am building is done and just plain have fun with what I have. I am sure I will get grief about this, but a C3 can be a very very fun car on a track and street without breaking the bank, unless you want to win every race. I am sure the racers here have a lot of valid points, but I get the idea you want a car you can drive and occasionally take to a track day and a C3 can fit that bill no problem.

glackore

Hey Sean 81,

I love the C3's so I am in for the long haul. Yes, you can do more with other cars or even x-race cars but they wouldn't be a C3. You can buy good suspension pieces and wheels/tires and anyting else you need for these cars. The thing I like is these cars are old school. The C4, C5 and C6 guys can't believe I can run with them and they have a lot more $$$ in their cars. I run a few autocross events and a couple of track days each year. Mostly I drive on the street and just have fun abusing my car. I have some videos of autocross runs on my YouTube channel - lt1vet - if you'd like to check them out.

Gary

FKING1

Looks like my 70 that I race and love. It is competitive with the C4,5 &
6's.

v2racing

Here's the way I see it. George is right about the C3 not being a great place to start building a race car. If you want to race one competitively, you better have a large bank account.

If however, you are just wanting to have fun, they can be plenty of fun at a local AX or track day. You don't need to win to have fun. I took my 80 with stock Gymkhana suspension (I had Bilstien Sport shocks and a bunch of camber and caster cranked in) and 15" all season tires to a couple of AX and had a great time. I wasn't the fastest, but nowhere near the slowest. Between the fact that I had a lot of power under the hood for the straights and I drive well, I beat some C5's, C6's, some Japanese and European sports cars, and a Viper with lesser drivers.

Come up against most of these cars with equal or better drivers and I would have been toast. Beating all the guys who couldn't drive was fun though. Of course you don't even need to beat anyone to have fun. Just getting out and driving hard is fun. A friend of mine brought his Buick Roadmaster out and had a great time!