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Vintage Racing; Level 1
Continued from link; VINTAGE RACE CAR DESIGN BLUEPRINT
First of all, (in my opinion) the 100% rule-book legal, vintage big-bore cars are almost non-existent at the racetrack. (A notable exception might be the high dollar, restored, pedigreed Trans-Am cars, R-Model Shelby team cars, etc). ie; the SCCA rulebook for AP & BP clearly states; no gutting of interiors, original carburetor model and size, original intake, head and block casting members, etc. It is also a similar scenario in the FIA AS rulebook. Therefore you will be hard-pressed to find any car in the pits today, 100% legal that would pass a 1969 tech inspection.
Nevertheless, for entry-level vintage racing it is an economical place to start by using OEM parts and fewer modifications to the car. While the “legal” car probably will not be the front runner, nevertheless there should be several cars your speed to race/compete and have fun with.
(1) Brakes: Good braking is a key element in reducing your lap times. You can probably shave more off your lap times per dollar spent on braking, than dollars spent on your engine.
Front disc brakes are a must have! Probably the best bang for the buck would be the 1965-67 Mustang (and Fairlane) front disc brakes together with 2-1/2” X 10” rear drums. This is what Shelby used back in the day and is still used currently in vintage racing, with good success. These 1965-67 Mustang units are 4-piston calipers made by Kelsey Hayes and are still available at your local auto parts store at a reasonable price. Caliper brackets are then needed to bolt the calipers to your drum-brake spindles. While original Ford brackets are getting scarce, they are available from aftermarket mustangs suppliers. ie; www.cjponyparts.com $70ea. The rear drums and backing plates are mid-60s full-sized Ford and stationwagon units. Rear drums and 15/16” dia. wheel cylinders are readily available at your local auto parts store. Porterfield Racing Brakes has several compounds of high-performance pads & shoes and a helpful staff to help you choose the best for your application. www.porterfield-brakes.com . I have used their R-4 compound with good success.
Other disc brake options include: 1968-73 Mustang, complete spindle and disc brake set-up (1 piston). In my opinion, I would also use the above 1965-67 Kelsey Hayes on all 1968-73 Mustangs, as they are much superior.
Other non-vintage options: 1975-etc Granada complete spindle and disc brake set-up (1 piston). In my opinion, these 1 piston Calipers are not as good as the above Kelsey Hayes 4-piston units. Another option would be aftermarket Wilwood disc brake kits, however beware you need to step up to the high-end Wilwood units before you will exceed the Mustang 4-piston Kelsey Hayes units. Do your homework before you buy.
Master cylinder: If non-power disc brakes are desired, I recommend installing a dual reservoir 15/16 master cylinder (ie 1975 Granada). If you have a high-performance camshaft creating low manifold vacuum, then you need to convert to a non-power master cylinder.
Proportioning valve: If you are having problems with rear brakes locking up under hard braking, install an adjustable proportioning valve (supplied by Wilwood, etc).
(2) Oiling: If you are serious about high-performance roadracing, then you need to install a road race T-pan to protect your engine from oil starvation during hard cornering. Canton brand is good, Aviaid is better/more expensive. Of course you should use a high-quality racing oil and with zinc additive if you have a flat-tappet camshaft. You need to install a mechanical oil pressure gauge with a larger ¼” tube. Then start the engine and bleed all the air out of the tube at the fitting where it connects to the gauge. This will make your mechanical gauge react instantly to any fluctuation if air is being sucked during hard cornering. If so, immediately add more oil to the pan and readjust the full mark on the dipstick.
(3) Tires: The only thing getting all that horsepower, handling and brakes to the ground is your tires. The better the tires are, the better your car is going to perform. Generally, vintage cars are required to run vintage bias type tires, although some clubs overlook/allow radials. Generally, 7”X 15” wheels on the front and 8”X 15” on the rear. These details should be double checked at your local club.
(4) Sway Bar: A 1-1/8 inch diameter front sway bar works very well and will greatly improve your handling. I do not recommend using a rear sway bar.
(5) Suspension: Replace any/all worn out or sloppy front suspension parts. You cannot expect your car to handle well with sloppy suspension parts, use polyurethane replacement parts where applicable.
A-Arms: While the upper A-arms are removed, re-drill/ relocate the mounting holes 1 inch lower as done on 65 Shelbys.
Monte Carlo Bar: Is needed to stiffen the unibody between the shock towers. Good export bracing to the firewall is also needed.
Springs: You need stiffer springs front and rear. Front coils; 600#-650# ( as you cut the spring to lower the car, the spring rate will increase approx 50#) Rear leaf; 4-1/2 leaf (has 1/2 leaf forward to help control spring wrap under hard acceleration) also, if you purchase the reverse-eye spring, less or no lowering block will be required to lower the rear of your car to desired height. For suspension parts, www.mustangplus.com has a great paper catalog. (also, if you plan to upgrade, see level 2)
Shocks: The original “single adjustable” Koni Shocks used on early Shelbys are hard to beat for the price. I’ve also had good luck buying good used Koni shocks off eBay at half price.
Optional; (a) Install a bump-steer kit. (b) Install a Shelby quick-steer kit = Pitman arm & Idler arm, together with a 1965-66 power steering gearbox.
(6) Strut-Rods: The stock front strut-rod bushings are especially troublesome. They are so soft and flexible, that it allows excessive fore and aft movement of the lower control arm, therefore your front end geometry is constantly changing especially under braking. A cheap fix is to disassemble the strut-rod bushings and cut the inner tube spacer a little shorter (shorten as needed – (as I recall about ½”) so that when reinstalled, the rubber bushings will be squeezed tighter and be much firmer. I do not recommend the polyurethane bushings as they binded and stress the strut-rods too much.
Another option; there are several aftermarket suppliers attempting to solve this problem with different designs, even the most expensive have their pluses and minuses and leave much to be desired. In my opinion, the best solution is mounting a hiem joint at the correct factory pivot point, this is low cost but requires fabrication and welding. This will be discussed in greater detail in the “vintage racing” suspension forum.
(7) Alignment: After you replace front suspension parts, (and assuming you have already got your car lowered to desired ride height), you should realign the front end for high performance track car settings: Caster; 4 degrees positive, Camber; 1 degree negative, Toe-in; 1/8 inch.
(8) Engine: After you get your car braking and handling well, then you can start adding more power. The quickest and easiest improvements come from Intake manifold, Carburetor, Exhaust headers, Camshaft. The engine forum would be a good place to get detailed specific information regarding your specific engine needs.
(9) Transmission: I assume it’s common knowledge that automatic transmissions are not suitable for high-performance road racing. Manual 3 speeds have much too “wide” spread between the gear ratios. Manual 4 speed “wide” ratios are less desirable than the “close” ratio transmission. Therefore the good old 1965-73 Ford toploader close ratio 4spd is the best bang for the buck, as it is much stronger than the old Borg Warner 4 speeds.
Note regarding Ford toploaders: small block engines use the long input shaft, big blocks use the short input shaft. Mustangs/Falcons/early Fairlanes used the short output shaft, Galaxie/late Fairlane-Torino use the long output shaft. All 4 combinations came in either wide ratio or close ratio, plus input and output shafts can be interchanged to achieve a desired combination. (I should also mention that Ford made some rare big input/output transmissions for 427/428SCJ cars that are probably more transmission than you need).
(10) Rear End: If you haven’t already, you need to upgrade to a 9inch rear end, with either a Detroit Locker, DPI black gold, Auburn, etc or a spool (you must decide on either 28 or 31 spline axles before you buy).
Notes; The Ford factory (clutch type) limited slip or traction lock differentials do not hold up very well. 28 spline axles will work, but 31 spline is better/stronger. Axles (and brake backing plates) from an 8” housing will interchange with a 9” housing of the same year/width, including either 28 or 31 spline.
Misc: For miscellaneous parts needed, www.SpeedWayMotors.com has a great “Race & Oval Track” paper catalog.
PLEASE FEEL FREE TO JOIN IN AND ASK QUESTIONS.
9/18/2011, 10:01 pm
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