Intro: '67 Barracuda..one
curve to another
More Tech: Lighting & Electricals Ignition Wires Distributor Fuel Strut-rods Mopar Roll Rate & Balance.
courtesy of www.plaftaphto.com
What's it Got ?
A '67 Barracuda Set-Up for Autocross & Ralley:
courtesy of www.plaftaphto.com
The key to any build is choosing components that work well together. There are two approaches to to take. One, copy what someone else has successfully done. The second method is to understand what ought to work together and try to put together your own package. And nowadays there's a third approach which didn't exist a few years ago, buy parts.that are marketed with a promise and hope for the best. To do that successfully, one of the first two approaches is needed.
1. SUSPENSION - Springs & Shocks
4. WHEELS - Rims & Tires
5. POWER TRAIN - Intake to Axle
Spring rates were chosen with the objectives that they be soft enough for use on rough roads, and that a rear sway bar would not be needed. Why no rear bar? Two reasons. The first was that a good rear bar was not available at the time. The second was that many road racers have found that the rear bar makes the car too twitchy. However, autocrossers might benefit from having a good adjustable bar. It is likely that the next change in rear springs may be accompanied by a rear sway bar. Availability is getting better again. Firmfeel and a few others are now making them. Unlike some aftermarket ones made in the 1980s-90s, Firmfeel's are indexed.
It is important to keep the balance between the front and rear springs. The handling line discovered emperically by Direct Connection (Chrysler) is a useful tool once you grasp it. The main difficulty in calculating the roll rates is in getting the spring rates for the sway bars and the leaf springs.
For a long time the car was set up with 1.04" torsion bars ( about 200 lbs./in. wheel rate), a 1.125" diameter front anti-sway bar, and 6 leaf 'heavy duty' rear springs made by Triangle Spring (160#/in). Result was as follows. The leaf springs were a little too stiff and had a little too much arch when new. Over time, the rear spring rates went down and the front/rear balance got better. However, after 80,000 hard miles, the right rear spring was worn out.
The new set up is with 1.09" Mopar Percomance torsion bars,
1.125" diameter sway bar, and Landrum asphalt track springs (200
#/in). The Landrum springs are on the crude side and
we had to send one back to get a matching set. Also the
second leaf does not come as far up and under the front eye to
give good support. The main leaf is nice and thick. (The
Direct Connection Chassis book recommends minimum main leaf
thickness.) Overall, I am very pleased with the car's balance. At
autocross speeds and in the dirt, very controllable throttle
oversteer an be fed in. With the earlier set up, wheel hop
was controlled mostly with the pinion snubber. Our goal was not to
use that method anymore as it compromises some of the cornering
dynamics. Raising the front spring eye reduced the hop and lowered
the car for autocross. For rough roads, stock spring eye
location has provided the needed ground clearance and suspension
travel. Handling on solid pavement is still plenty good
Front Sway Bar Linkage and SPAX Shocks:
WARNINGS about Swaybars.
Chrysler only put sway-bar tabs on cars that came with sway bars. Mine were welded on afterwords, but tabbed lower arms can still be found. Note that there were several changes made in K-frame and sway bar designs over the years. If you fabricate you're own, position them in stock locations or check the linkage geometry with the control arms in full compression.
Rear sway bars can easily cause oversteer if not balanced by much increased front roll rate or shifting of weight. Add front anti-sway bar and or increase front torsion bars first! Oversteer (fishtail and spin) may only show up on the street in the worst situations such as high speed turn on slick surface.
I've installed the SPAX shocks. They are relatively cheap (for adjustables) and have proven to be far better than the KYBs on the street in terms of ride quality and provide similar if not better control. However, the SPAX shocks are designed for Australian valiants and need some minor mods to fit the US & UK A-bodies. Front shocks need the bushing sleeve opened up very slightly with a drill or reamer. SPAX ran out of bushings for the rear shocks, so you need to install your own bushings now. Model numbers for the SPAX shocks are G480 & G481.
For the rear shock bushings, I used polyurathane Chrysler 5/8" Shock Bushing (Energy Suspension #9-8112G). Apparently the 11/16" inner diameter is not available. However all of the other dimensions are correct, so its "just" a matter of drilling out the center. Although easier than drilling rubber, the bit still wants to tear rather than cut the soft material. Freezing helps make it stiffer. After drilling, I cut the bushings in half with an Xacto razor saw and a sharp utility knife. By making two halves, the bushing does not need to pressed in.
SPAX Features: The SPAX shock is single adjustable, but each click effects the compression only about 1/3 as much as the extension motion. This is good. Adjustment is also external. Price is about $80 to $100 each (US).
Credit for discovering this application of the Aussie Valiant shock goes to Dave Mapes who tried them out on his '66.
The KYB Gas-a-justs were a cheap non-adjustable shock. I hear bad things about the ones made in recent years, but I had one leak after about 6 years and it was replaced for free. In the past two to three years (as of 2016) both Bilstein, Edelbrock, and others now offer performance oriented shocks for the 1960s-70s mopars. No personal experience with them, but they are worth looking into. Tim Werner effectively used a Bilstein combo he made for his high speed track car (Project Valiant). Shocks are very important for both vibration (high frequency) and roll control through curves (low frequency), so most serious competitors look for dual adjustable shocks to tweak the most out of the car.
Front Suspension Alignment and Bushings:
Caster and Camber
is adjusted by cams on the upper control arm. Moog adjustment
cam kit comes with longer bolt heads than stock. Offset
bushing kit sold as "problem solver" will get more caster or
Alignment is very important for
both how well the car tracks and how will the tires grip when accelerating, turning and
braking. Here is one place where the factory specifications may not be the
best. First, tire construction and
changed, generally for the better, but generally
also requiring more camber. Second, many roads at the time had a high crown and the
factory had to consider that. Finally
they had to make sure that 99.5% of their customers could
turn the steering wheel. With these considerations, more positive caster,
and more negative camber with factory toe generally works
well. When using competition tires, check with the tire
manufacturer for the recommended camber.
Kelsey-Hayes 4 piston calipers work
very well, but with a car that sits alot, brakes need to be bled
every year to remove moisture and rust. Dry brake fluid is
also critical for good pedal and to reduce the chance of boiling
with repeated high speed stops. The Valvoline DOT3/4 seems to stay
cleaner than the Castrol LMA. .
The power booster was not liked by me and was sold, along with the stock proportioning valve. (Stock - but not from this car -it was an all drum brake car originally).
Parts availability for the brakes seem to run in cycles. Usually Kelsey Hayes calipers are readily available as they are very similar to the versions used on Mustangs and some Corvettes. Rotors are sometimes hard to find, and some of the aftermarket ones are not very good. For example several years back the Bendix were not balanced and the "hat" section tapped the caliper piston boots every rotation. I returned them! Drums were unavailable for awhile but now can be bought from any parts store.
Chrysler made running changes to the drum mechanism, adjusters
and shoes from 1967 through 1969. These are documented in
the TSBs and MTSC booklets. In 2015 I switched to the 1969 style
adjusters and shoe frames.
For linings, I am currently (2016) using Porterfield's
R4S on all both pads and shoes. All of the previous linings
I used are no longer available. The reasons for trying the
Portefield will arc the shoes to match the drums; As a multi-use car, a low temperature street lining was needed for most situations; They should hold up for first time track use and will be compatible with R4 if/when high temperature track linings are needed. For mass marketed linings, one can usually check the friction codes on the sides to get a relative idea of their high and low temperature perfmance (street use)..
The '67 A-body has a weak idler arm. I should have swapped the K-frame when everything was out! Every 2 or 3 years the idler arm wears out. The '67 idler hangs down from a stud (same design as the earlier A-body idlers, but the idler for '67 is a one year only part). In 1968 Chrysler changed the design to a through bolt. Lesson. Don't autocross or rally with the '67 design if you can help it! The car finally got a '68 K-frame in 2003.
A manual steering box with the p-part 20:1 ratio worm gear was used for quite a while. This is a relatively streetable ratio depending on - how much parallel parking, how big and heavy the wheels are, and what the scrub radious is. Once you are moving its fine. However, this ratio is a little too slow for the slaloms. In 2003, a 16:1 steering box was installed. It requires significantly more effort to parallel park the car. A big stock diameter steering wheel helps with leverage although some find it 'slow' to turn when racing.
Why manual steering? There is weight savings using the aluminum manual box over a power unit. In addition, the stock power steering units lacked road feel. However two companies sell firm feel power steering boxes which overcome this problem.. Some who have used power steering in competition report the need for a cooler.
This car is using the original 5 lug - 4 inch diameter bolt pattern. For the record, by 1968 some of the race prepared cars had a 4.5" bolt patterns, either creeated with various combinations of parts pulled from the bigger cars or using a limited run of disks and hubs. Many people today switch to larger pattern by changing spindles, front brakes and rear axles. I haven't.
Rims: A fairly limited offering of wheels is available for the small bolt pattern. The factory only offered steel 13 and 14" rims for the small bolt pattern except for the 1969 Kelsey Hayes option.. The widest width was 5.5" which was OK for the E70-14 tire size which isroughly the same dimensions as a 205/70-14. Advantages of staying close to stock tire and wheel diameter include lower weight and lower ride hieght compared to larger and taller rims and tires. In addition, the option of using tall sidewalls provides a means to drive on really bad roads with one set of tires and switch to a lower profile for competion. Disadvantages are a currently somewhat limited offerings in performance street tires for 14 and 15" rims.
Wheel Options for aftermarket 5 on 4" bolt pattern rims.
(Look around, More are now available, 2016)
1 - Centerlines. Two reasonably priced rims styles, but one is really for drag racing only(no air vents to help cool the brakes).
2 - Crager SS. Look nice, but are at least as heavy as stock rims. Available both new and used.
3 - Ansen Slots (and copycats). Cast aluminum rims which are fairly common and strong. These are what I use now. They are fairly light and strong, and came in 14x6, 14 x7 and maybe other sizes. American Racing Equipment now makes a new version in 14 and 15 inch diameters.
Watch the front fender when running 215/70 tires on the 14x7 with the front lowered. The backspace isn't quite deep enough, and they sometimes touch. The shouldered lug nuts are a pain to install on stock length studs. 14x6 cast slots about 12 lbs. 14x7 cast slots about 14 lbs.
3b - You might also find other style used rims such as torque-thrusts, or the recalled Kelsey Hayes. The latter actually being a relatively sought after piece (unlike most small bolt pattern rims) will usually have a very high asking price.
4 - Custom Steel. Several companies will put a small pattern centers into ralley style or stock style 14" and 15" diameter steel rims. I did this for my first set of autocross rims, 15x7 ralleys, about 19 lbs. each. Relatively cheap.
5. Custom Aluminum. That's what I was using for autocross. Circle Racing (now Spinwerks) makes a spun rim. Whether they would do well for street and ralley use I do not know, but are certainly fine for autocross and track days. They do flex under load, always a problem as rims get lighter. For more money there are Bogart rims (also aluminum, but a stiffer construction). 13 lbs. each. for 15 x 7.0" Circle rims. A lug nut with larger outside dimensions is a help. A fellow on e-bay is now offering 17" rims with a vintage SS look. I don't know anything else about them.
With the 15" diameter spun aluminum or steel rims,
4.4" back space is about the limit before hitting the upper
balljoint. Going to 16" rims would probably clear the
balljoint. A 7" width is just a bit too small to carry
a 245/45-15 tire decently. There appears to be room to go
outward to 7.5 or 8", but this will also move the centerline out.
This will increase front track. In general this is a good thing,
but it also increases the scrub radius, which especially with a
manual steering car, is a bad thing. Stock offset was about
0.7", and 7.5" rim with 4.4" backspace is about 0.2" and with an
8" rim would be about 0.75" away from stock.
Fall 2001. BFG R1 245/50r15 tires on 15 x 7 Ralley Rims
(photo courtesy of Steve Claymen)
June 2002 Hoosier TDs on 15x7.5 Circle Racing Aluminum Rims
The tallest tire I've run (to gain ground clearance for the headers) were 225/70r14 BFG Radial T/As. These tires easily fit, but under extreme conditions (full jounce-turned hard), the fronts just touched the fender trim. After removing the Headers by Ed, the 215/70-14s which serve fine. This size has also worked fine with the new custom headers which have great ground clearance. Firestone's Firehawk Indy 500 have better traction than BFG's Radial T/As on both pavement and loose surface but are not currently available.
Now to seriously autocross, the street tires don't cut it. Sticky tires are more fun and save the street tires for what they are better at doing. In my opinion, 225/50r15 are not wide enough to make the car truly competitive in Solo 2 autocross competition, but its a fairly available size and keeps the ride height low, while happily fitting on 7" wide rims.
In 2001 I squeezed 245/50-15 BFG Comp T/A R1s onto a set of 15x7 'ralley' rims. This made the shoulders round and not all of the tire could be used effectively. Steve Wall had this size tire rub on his car during manuevering (see link to autoxcuda). I ran a little less backspace on my rims (4 3/8") and had only a little rub on the rear leaf springs and on the front sway bar and none on the sheet metal.
After deciding I liked the 245/50s, BFG basically got out of the market. This left Hoosier the only manufacturer of 245/45-15 competition tires. (well Avon did also, but...anyway) I went with the Hoosier 'Street TD' bias ply and what I thought were 15 x 7.5" aluminum rims. It turned out the rims were only 7.0 inches wide. Oops! Also, while the Street TD very hard to break loose, it provided less directional feel than the radials. Fast forward to 2006. In a back to back test, Dave Mapes and I found the 5 year old TDs were still fun, but significantly slower for autocross than a somewhat old set of 225/50r15 Toyo RA1s. Guess what tire I'm running now.
Wheel & Tire Weight Comparison:
( mostly weighed on a bathroom scale )
|Stock '67 Steel
||14 x 4.5 JJ||15 lbs|
|Cast Aluminum slot 14 x 6||14 x 6
||13.5 lbs||Firestone Indy 500||215/70r-14||24 lbs||37.5 lbs|
|Cast Aluminum slot 14 x 7||14 x 7
||14.5 lbs||BFG Radial T/A||215/70r-14||24 lbs.||38.5 lbs|
|Steel "ralley" rims,||15 x 7"||19 lbs.||BFG Comp T/A R1||245/50R-15||26 lbs.
|Circle Racing spun alum. rims||15 x 7.0"||13 lbs||Hoosier T.D||245/45D-15||17 lbs.||30 lbs|
| Circle Racing spun alum.
||15 x 7.0"
||Toyo Proxes RA-1||225/50r-15||21 lbs.||34 lbs.|
| ARE Ansen Slots
||15 x 7.0"
||Toyo Proxes RA-1||225/50r-15||21 lbs.||38 lbs.|
|Engine bay in 1991. Holley
single plane intake
hood clearance. Chrysler Mopar performance ignition,
system and Mecca waterless
coolant system still in place.
MSD 6T replaces the Chrome box, original style air cleaner housing, and horns back in original location.
|2016. New engine with
LD340 intake, drop base aircleaner with contoured lid,
coolant overflow recovery, breather cross-over and
Intakes: I've experimented with both a Holley 650 and 750
vacuum secondary on a Holley single plane Street Dominator, and an
Edelbrock LD340. After studying the runners on the LD340
versus the newer RPM, it appears the RPM probably does a better
job at maintaining velocity in the lower rpm ranges. I'll be
trying one next.
Carburation. One issue with autocross is that the carburetors seem to have a penchant for flooding out during severe braking. A cure is to use jet extensions along with a notched float. Tuning carburetors for performance often requires more than simply changing main jets. Urich and Fisher's Holley Carburetors and Manifolds provides a solid explanation of how the circuits work. Chrysler's MTSC series has several pamphlets covering Carburetor fundementals as well as specifics for both Holley and Carters. I've recieved very good help from reading Jmarkaudio, 'Tuner', 'Shrinker' on several forums. Currently Racing Fuel Systems forum is the place to go. Ignition timing is also real important to tuning and that is discussed there as well.
Exhaust: Until 2015 the 340 Exhaust Manifolds were the
best option for my Barracuda as ground clearance is very
important. I had been through several rounds of headers that
did not fit this car or had poor ground clearance. However I
do believe that headers can be one of the surest ways to improve
power and efficiency. Tests by a magazine show that
even a less than ideal header could make more power than even the
340 manifolds except right around 5400 rpm, where the 340 manifold
does quite well. Additionally a 1968 Hot Rod dyno test of 340
engine modifications suggests the same thing.
Exhaust that is exiting too slow can get drawn back into
the exhaust port during overlap, especially with performance
cams. This is an issue with velocity as much as it is mass
and volume. Racers also are interested in wave reflection at
junctions and other discontinuities. These reflections can
assist or resist the flow in various rpm ranges. Some very
good guidance is available from Larry Meaux's Pipemax
software. In addition, Calvin Elston has been very
generous in sharing his approach, experiences and questions
in his blog
and on Speedtalk forum.
My experience has been that even with manifolds, too large and poorly positioned X pipe is no help and may be a hinderence. Only Accurate Exhaust offer tailpipes specifically to clear the '67 gas tank strap. They also stock a very nice gasket for headpipes to 340 manifolds. On my car, their reproduction pipes hung a bit low. Don't know if it is typical or just this car. We flow tested the 2.25" mufflers Accurate supplied vs. the 2.5" Dynomax Super Turbos. The Accurate muffler was very good for a 2.25" muffler, but the 2.5" Superturbos clearly out flow them. Resonance with the Accurate muffler is much less than with the SuperTurbos. However I suspect the combo of large exhaust, x in the wrong place and more restrictive mufflers was hurting performance. Unfortunately some other changes (such as distributor) means I don't have back to back testing to verify this.
Headers that fit: More options are now availablefor
A-bodies than there have been in years. Headers by Ed has (had) an
easy to install, equal length design with an clever joining of the
tubes into the collector that reduces turbulance. However
they hung too low for the roads of NJ and
Pennsylvania. Doug and TTI both offer headers for
A-bodies with LA engines that reportedly fit fairly well.
Schumacher offers a tri-y, and Layson's has an incarnation of the
'spitfire' short header. However I was determined to go with
custom headers that would fit the car, have low angle merges,
reduce reversion at low rpm and have good ground clearance.
We used a custom made flange for a smooth transition from the
heads to a 1.5" diameter primary that stepped up to 1 5/8.
Details of this build are in this
post on the Speedtalk forum Using stainless steel
reduced the need to experiment with thermal barrier coatings.
Headers by Ed
Results of Contact with Pavement! Headers & Remote Oil Filter
Even where there was no physical damage the Jet-Hot coating did not hold up as well as expected. Its possible temperatures exceeded the 1300 degree limit.
All those gaskets and flange connections actually sealed pretty well and the bolts were accessible. Ed did a good job with flanges ground flat for leakfree sealing and bolts properly tensioned.
The Mecca coolant was rather expensive and was not all that practical on the street. I will admit the engine never pinged with the stuff (at least that I can recall). I lost all of it a couple of times, like when the cluthch fan went into the radiator. I stopped using it about the time I went from a 6 cylinder radiator to a larger, high flow unit. Not sure if the stuff contributed to the recent failure of a majority of the steel expansion plugs or not. The theory behind the Mecca system is that better cooling and less corrosion is possible with a properly formulated propelyne glycol than a water- glycol mix. The system runs at atmospheric pressure because the heat transfer is very efficient, using nucleate boiling to cary heat away from the cylinder walls, but it never turns to steam (no water in it). The system runs at atmosphereic pressure. (The reason for a pressurized system is to increase the boiling point and prevent the coolant from vaporizing, eg. turning to steam. Steam or vapor does not circulate very well although it does absorb a tremendous about of heat when it initally turns from liquid to vapor).
Current cooling system is simply a standard high flow radiator and good old green stuff with distilled water. Unlike the oil temperature. There has never been a problem with the cooling. (Except the fans self destructing - a Chysler flex fan I picked at a junk yard to replace the cluthc unit subsequently sent half a blade through the battery outside of Fredricksburg Virginia) I now am using a new, Mopar Performance clutch fan, and no shroud.
Remote Oil Lines, & Accusump:
The accusump was great. It was located behind the rear seat and connected with a braided -10 line under the carpet. Unfortunately, the lines coming out of the engine were a recurring problem. The small block mopar oil adapters are a poor design in every respect. They are not great for flow, like to leak, and tend to rotate when the external lines are being attached to them. The recomended way around the adapter is to tapp right into the block. This could not be done with the engine in the car, I tried! Additionally, the rubber inside the Aeroquip hoses would start to get real brittle from the heat, and after about 12-18 months they would begin to seep oil. Therefore both the accusump and the remote filter were eventually removed.
Ignition: MSD 6T with rev limiter, adjustable timing control, blaster 2 coil, Taylor Wires, Champion RN9YC .045 gap
Three voltage regulators and one chrome box later, it is my opinion that the Mopar Performance electronic ignition items leave something to be desired. I keep one orange box as a back-up, and run the MSD 6T instead. Since switching to the 6T, the electronic voltage regulator has not failed. Talking with others, if it does fail, the original points style regulator will work fine in this application. The MP mechanical only distributor was great, but gas milage suffered. I rigged an advance mechanism that switched the MSD timing retard box on and off . That worked OK, but found it simpler to simply use a MP distributor with vacuum advance. My thinking is that it probably improved part throttle response as well.
The Taylor wires got overheated sitting in traffic for an hour with air temperature of 95F. What happened was the insulation at the crimp failed when one of the wires was removed. These were replaced ASAP with a better protected wire..but it wasn't really a better wire. I'ld go back to the Taylor's or try the MSD which are reputed to have a slightly higher heat resistance than the Taylor's. I've made a comparison chart of wire resistivity and more comments.
Charging & Lighting:
After suffering many years with a headlight system on the brink of failure, a major upgrade has been completed. The addition of an "60 amp" Tuff-stuff alternator from Hurst Auto & Truck has mostly solved the low rpm charging problems. A March underdrive pulley on the crank stopped the tendency of throwing the fan/alternator belt at high rpm shifts. But alternator output at idle was too low. A bunch of calculations later showed that the underdrive pulleys could not be the main culprit - alternator speed at idle was over stock speed because of the high idle is now around 1000 rom (stock is 500rpm). I've been using H4s headlights, which draw the same current power as stock, but light the road far better than even halogen sealed beams. The Hella Vision plus is a good headlamp, and passes inspection in NJ. Recently, I installed Cibie E-code lamps in my Grand Wagoneer, and I must say that the Cibies provide a more even light, and less annoying cutoff than the Hella Vision plus, or the regular Hella H4. In fairness, the lenses on the Hella's are now chipped up, mostly from truck stones driving down south a few years ago. Time to replace I'm afraid.
Page with Details and Links on Improving the Forward Lighting
Intro:'67 Barracuda..one curve to another
The Story of the Restoration
Grand Wagoneer Page
Pictures from Autocrosses 1989-92 in NJ, Other cars including my old '74 Nova 250 cid 6 that I ran in H Stock.
Fuel Delivery Facts and Figures
Ignition Wire Comparison
Improving Forward Lighting & Electricals
Handling Theory for late-'60s to mid-'70s Mopars
Strut-rods and Bushings
If you take advice, or copy something I have done, you are on your own. I'm just trying to be helpful. You need to make your own decisions, and know about or discover the risks before barging ahead on any endevour.
If you steal something I have written, or a picture I have taken or drawn, you are a thief. Plain and simple. If you wish to quote something, you are free to do so. All I ask for is proper credit. If you wish to quote or copy more than a couple of lines, then you must get my permission.
e-mail: M. Grubel
mgcudat rev11 2016