Building 68 Barracuda track car

I have a 68 barracuda fastback, which used to be my daily driver many years ago, until the engine blew. I've decided to turn it into a track car. I plan to use it on track days at Willow and such places, and in Lucky Dog endurance races. So, it will have a full roll cage and tubing structure all the way to the front of the rails to make it a stiff racing chassis.
I never thought I'd get around to this due to the cost, but I took stock and realized after decades of mis-spending my youth, I have almost all the parts I need sitting in the garage.

Question is: Does anyone here have experience, or knowledge of, specific preparation techniques for a 68 Fastback Barracuda? Particularly aerodynamics, but also durability parameters for 8 hour + races.

I will be using a 340 block probably with trick flow heads. I have a spare close ratio four speed out of a dead TA, and an aluminum case for an A body I can put the gear set in. I will be using an 8-3/4 and brakes all around from Dr. Diff; the 13 inches with Viper calipers and the Ford rear discs; and I have a couple sets of Kit Car springs.

A few of the aerodynamic issues I can see right now are 1. an appropriate rear deck spoiler; 2. extractors or venting of the hood for cooling and lift reduction issues. 3. general smoothing of certain areas of the car to lower Cd, windshield edges, etc.
I expect I'll also need to install at least a rear end cooler, and possibly a transmission cooler, which is where people's experience would come in.

Any knowledge or experience is welcome, or links to work people have done in the past with this particular car.

Thanks,
Robert

Brian Garcia has an ultimate 67-9 B'Cuda fastback setup for road course racing... runs vintage historic W2W events in the midwest. He's been very successful and a crowd favorite.

In this order:

1. Driver track/seat time

2. safety equipment ( makes the driver braver)

3. Tires

4. Suspension

5. Brakes

6. Oil Pan

7. Engine/trans

8. Weight reduction

9. Aero

The classic car is definitely well-maintained. It looks brand new despite its age.

Look through this thread for a picture of the worlds most aerodynamic 2nd generation Barracuda - the Blowfish built by Rad Rides. However, none of this is necessary for track day excursions.

https://board.moparts.org/ubbthread...lt-and-couple-cool-cars.html#Post2955319

I have sent a PM to Brian Garcia, but I see that he posts very rarely here, so no idea if he will answer.
Does anyone know how to contact him who would ask his permission to give me his personal contact information?
I expect that he has plenty of lessons learned that would save time and effort going down some wrong roads.

Any help is appreciated.

Thanks,
Robert

Also, I just remembered Steve - autoxcuda and his Barracuda sedan. Hopefully he'll see this thread and chime in.

I'd be very surprised if you need to worry about aero. We had Tim's red Valiant going 160 mph on the front straight at PIR without much aero work. Just had a big homemade air dam up front and that was it. Had the car as low as it could go while still having a little bit of suspension travel. If you are staying with the factory T bar and leaf spring suspension then you most likely won't be able to get going fast enough around a road course to worry about aero.

I also think you'll need more than a 340 with TF heads and a four speed before you need to worry about aero. The last engine we had in Tim's car was a 427 with heavily ported heads. It was a brutally fast street car but not a real terror on the race track, especially with high gears out back and a four speed. If you want to scare yourself I'd suggest a boosted Gen III Hemi and a 5 or 6 speed transmission.

Thanks Andy. I'll keep that in mind as I'm doing the design and math.

My goals are to have fun and learn to drive better. One of my design parameters is to use as many parts as I have on hand in my garage, which as I said earlier comprise a lot of what I'll require.

I'l be looking at some of the various racing leagues, the more entry-level ones, and try and get some data on power to weight ratio's versus speed and time at particular tracks. That should give me an idea where I might stand, and how I might need to adjust my build parameters.

I've read some of your previous posts about turn-of-the-century Corvettes being a better option for a low budget track car, and I mostly agree, especially if you're talking about unmodified, ie low stiffness, 60's 70's Chrysler chassis. However, A full space frame tubing chassis welded onto the existing car changes that equation somewhat.

I don't see that a properly done torsion bar and rear leaf spring design would be a hindrance to track speed. However, you did write factory T bar setup. The one major issue that can't be overcome building a car on the factory chassis is that you are severely limited as to how much you can lower the front end as the lower control arm comes in contact with the frame rail. Historical way to fix that is to raise the front sub frame in relation to the rest of the chassis or as the Chrysler books say "lower the body on the frame". But now we're in a whole nother world of high dollar.
What would be a simple and effective solution would be to use a drop spindle. This is a perfectly acceptable design that would lower both your CG and your front role center. However, I've done the research, and I have to agree that there isn't a good one available. A properly designed spindle, with the proper materials and processes, could be produced by casting. But, I'd need a lot of data like fracture toughness, static load test results, dynamic load life test data, and assurance that it wasn't made in China, to be able to trust it. I don't see getting any of that from the current manufacturers.

So, I will set my performance expectations for what I can do based on what I've got, and have as much fun as I can with that and learn what I can at that level. I'm not looking to set the world on fire (for now). And I will use the Barracuda instead of buying a Corvette because 1. I have a clean fastback chassis I bought for 500 bucks many years ago, and 2. because the Barracuda's cooler.

i'm actually kind of surprised you didn't see any aerodynamic affects over, say, 120. But, every aerodynamic configuration is different. So I'm still going to look into finding whatever historical data that I can. People have been racing this set up for about 50 years. And I'll do my own testing once I get the thing together.

Thanks for your input. I may be sending you requests for lessons learned in the future as I'm working on this thing.

Robert

It is a race only setup then the 340 can be built with high compression and a healthy cam which will raise the power level. The problem is that a big cam kills the low speed torque and if the car only has four speeds and a tall gear in the rear then you'll kill the clutch pretty easily. That was a real issue with Tim's car since he had some super tall gears out back so he could go 160 mph. The super tall gears made it tough to load on a trailer or start on a hill. That car really needed a 5 speed or maybe even a 6 speed and that was with a 427 inch engine that had a bunch more torque than any 340 will make.

Maybe, but what you have written in your responses, so far, do not back that up.

This seems to be common whenever these threads pop up, and as I responded, and Andy touched on, driver skills almost trump EVERYTHING else you have touched on, and your concern/focus about aero supports your naivety on the subject, and don't be offended by my bluntness, at one time everyone on this site also started out knowing basically nothing. That doesn't imply you know nothing, but that you still have a bit to learn relative to others here.

If you want me to sugarcoat my answers, sorry, ain't going to happen, I have nothing to peddle.

Robert -- I'm good friends with Brian... locally live nearby. I'll reach out to him for you.. he's a pretty busy guy.

PM sent to you just now...

With rubber compounds we have available and the shock tuning, aero is and can effect the car at an speed over 40 mph. Don't believe it, look at ay local SCCA autocross. Rarely see speeds over 70 mph, and they have the wings to make up for it. Once I started seeing the mechanical cornering of the Road Runner hitting its limits, you HAVE to start looking at the air. Most of the undesirable effects my car had mechanically and in driveability started metastasizing and curing once I started playing with the aero of the car. 2 biggest gains: keep air from under the car and from under the hood. My car developed an awesome squat at speed and stability once i played with rake and attack angle as well.

"Once I started seeing the mechanical cornering of the Road Runner hitting its limits, you HAVE to start looking at the air. "

You do realize how far into the OP's future on this project that is, right?

We also might disagree on the primary purpose of useful aero effects, IMO, its to enhance the proper mechanical set-up of the car, not fix other poor choice problems.

And it was #9 on my list.

Well, aero matters from about 60 on up; that was proven by Car and Driver decades ago in a fairly thorough experiment.
That said, there's a lot more to be gained, in larger amounts, with the basics, as already pointed out.
OP needs to decide on his budget, and I'd advise developing skills before spending $$$ building the car.

The aero gains on that body primarily involve the deep & open grilles and a profile that benefits from a rear spoiler.
I'd flush or block the upper grille openings, use the valance for intake, add an air dam, and vent the hood.
A rear spoiler that extends up from the upper rear face of the trunk lid works pretty well; that face has a decent angle.

as far as building the car:
Figure out the who you're going to spend most of the time running with and get their rule book. That will outline what you can and can't do to your car. Unless you want to just get bumped to an unlimited class.
Once you have the rulebook my rule of thumb is:
1) chassis, make it as stiff and safe as the rules say
2) determine tires, budget/rules
3) suspension, rules/tires

Everything else comes after that. The most important part is the nut behind the wheel.

As Cudazappa has stated... Best advice to anyone intending to run with a club at sanctioned events... is to first look at their classes and rules. Even if you aren't immediately going to run with a club... build the car according to some rules and classes from an organized club... you'll be glad you did in the long run.

If I understand this discussion so far. member Andy is the only one to maybe poo poo aero IMO.

To restate my point, on my original posted priority list for areas of concern for the OP's project, aero is the LAST issue of 9 he needs to deal with.

I never said nor implied to anyone it has no effect or nor importance at any speed.

As I believe as a matter of fact, and supported by my posted builds here over time,, IMO, I'm indeed a huge believer and follower of Aero solutions.

Strangely I suspect and noted just for conversation sake, at the F1 level, my list is almost completely reversed, but then of course, this is not F1, stating the obvious.

Aero is important on cars that go fast. My response was to the OP who doesn't have a fast car. His car isn't even built yet and might never be built so my response was aimed at helping him prioritize the build process in an effort to help him actually get something accomplished. Many (maybe most) home built cars never see the light of day much less make WOT trips around a road race course. For a guy working in his garage to succeed he needs to focus on only the highest priority tasks. Aero is way, way down on the list.

Now if the OP gets the car done and starts making laps in the 150 mph range and he comes back here asking for advice I'd then tell him to take a look at some aero tricks.

i will say this. at a local dirt track the "new" late models have all the best aero noses and engine tech gained from years of cut and try. just a few months ago , a driver cut a lap at 16.118 ... the track was totally re-clayed and in the best shape in over 50 years. back up [37 years] to 1984 .. i have a news paper article stating a driver set a new track record of 16.112 at the same track!.............. 4/10s mile banked and fast track. so much for all the new improvements to the track and the new tech advances on aero, chassis and engines. they even have $2,000.00 [each] shocks ! get the basics for your class and learn how to set up -your- car.... now if you run Daytona , or super hi speed tracks add aero to your basics list.. master the basics first. dont over think it. you will find that in its self is a huge task......

As someone who has had a front end get LIGHT on the back straight of Buttonwillow in a customers car because someone said we didn't have to worry about aero.....

...you should always look at aero if you plan on running on the track.

I'd suggest selling that 340 and 4 speed to the resto crowd. You can put a 6.4 Hemi/six speed pullout combo in your car for less than you'll build the 340, and put the sale money towards that. This gives you almost 500HP with dead nuts reliability and no oil leaks.

Once the drivetrain is sorted, I'd look at suspension. I'll make this one statement, shocks are VERY important. My opinion is unless your willing to put a clip on the car, work with what you got. Hotchkis has good stuff. The bolt on front suspension systems available basically move your cars geometry from the late '60's to late '70's.
If your willing to change the front, couple of places sell the rails that mount C6/C7 corvette cradles (rear IRS/transaxle too!). It's a cheap way to get good geometry, suspension components, and brakes in one swing.

Your going to want the widest tire you can fit, preferably a square set up (same size up front as in back). This helps balance the car. The weight is biased to the front (even more under braking), and those front tires are what lead on turn in, so wider the better. This may be tough utilizing the factory suspension, so flares may be necessary (note of caution, adding positive offset will change the scrub radius). Upgraded brakes will be dependent on what size tire you put on it (both width and diameter) and intended use. Autocross cars really don't need big brakes. Track cars can benefit from them. Huge brakes with huge brake torque are pretty useless if you can exceed the mechanical grip of the tire.

Weight reduction is probably the biggest bang for your buck. The car is more responsive and requires less brake and tire than a similar heavier car.

Aero on these old cars is important. They generate so much lift. My initial goal would be to decrease the lift, more so than adding downforce. That is basically the same thing, but if your generating 200 lbs. of front lift stock, and can reduce that by 150 lbs., you did increase downforce, but in my mind your still just reducing lift. I call it downforce when I've overrun the lift numbers. An air dam and splitter to keep air from under the car will go a long way, and cheap to make. This little add will be your most significant "reduced lift" mod you will make. Try to avoid a huge spoiler on the back until you can ascertain the aero balance of the car. Adding a ton of rear downforce on a car that is already wanting to lift the front makes a very unstable, scary drive, as your just compounding the front lift issue.

Only other advice is have fun. Your not in competition with anyone but yourself. When you get it on track, only make changes when you can string together a series of consistent lap times, then, only one change at a time and preferably A-B-A testing.