Twenty Tech Tips For Street Survival - Weekend Tech
The Lowdown On Making Your Mopar Work On The Street
From the September, 2001 issue of Mopar Muscle
By Steve Dulcich
If there's one thing that could be considered a cut above owning a Mopar musclecar, it's running that Mopar on the open road. Sure, there's the so-called "trailer queen" part of the hobby, but for most of us, the thrill in having something we can use. Hey, after all, it's your Mopar, and you can very well do what you want with it: shine it, show it, trailer it, race it, or drive it. That said, if you like your Mopars real-world ready and driveable, here's some food for thought.
More often than not, when building a hot engine for that Mopar, a hotter cam and aftermarket valvesprings will be part of the package. While the easiest thing to do is squeeze the springs under the retainers, street (or race) survival depends on checking the basics. For example, what will be the lift at the valve with the cam and rocker ratio combined? Check for clearance between the top of the guide and the retainer at full lift. MP recommends a minimum clearance of .050 inch, but more is better, and don't forget to include the thickness of the guide seal.
Also, coil-bind clearance is essential, with a minimum of .050-.100, depending on whose specs you trust. Most springs are specified for coil-bind height; just subtract the valve lift from the installed height to decipher how much clearance is left. On the subject of installed height, a spring's load capability is directly proportional to its height, so knowing the load at the installed height is critical. Finally, for street use, don't get carried away with mega-big drag racing spring loads. Be realistic about your requirements-based on rpm and cam design-and select a spring that will perform the job without prematurely wearing out the valvetrain and pounding the seats. If in doubt about what's needed, consult an expert.
2. Oiling Options
A good street oiling system can range from radical and racy, such as the Milodon system pictured here, to OEM stock. The key is to match your requirements to the rpm range and use of the engine. The stock system works fine in a stock or mildly modified Mopar engine, big-block or small-block. A high-volume pump, coupled with minor mods such as a larger 1/2-inch NPT Hemi pickup in a big-block, along with some subtle passage massaging as outlined in the MP books, are all it takes to handle engine speeds through the mid-to-high sixes. Consider a windage tray mandatory in either engine family, and think seriously about adding a sump baffle in any open-sump pan to keep the pickup in the oil. Most importantly, stay clear of low-hanging, drag-style deep-sumps if any real street use is part of your plan; one pothole or speed bump will ruin your entire day.
3. Hassleless Headers
Headers add power, but low-clearance pavement draggers add headache, especially in the wilds of real street use. Rather than banging 'em in, get good ones that don't hang down. TTI makes a wide range of real full-length headers, such as the A-Body units above, which tuck much nicer than most. Other options include designs such as tri-Ys, shorties, or running the stock iron manifolds, though power won't match the benefits of full-length tubes.
4. Quality Counts
Adding reliability means shelling out for the good stuff where it counts. Here, we're preparing to install super-duty Arias forged racing pistons hung on bulletproof Eagle rods into a street engine. If that engine means anything to you over the long haul, stay away from the cheapo replacement goods and step up to real performance parts. Hypereutectics and forged slugs are hardier pistons than bargain-basement cast hand grenades and well worth the dough. Upgrading the fasteners, first in the rods, then the mains, and finally securing the heads, is the name of the game for long-term piece of mind. As power and rpm levels step up, so does your parts list, including aftermarket rods, forged cranks, blow-proof dampers, and so on; the list is endless. Those cheap, stock, old, or nasty parts may survive just fine, but be prepared for things to go wrong if you choose to roll the dice.
5. Secure Sealing
For stock or mild engines, that $29 gasket special may do the job, but blowing a head gasket or sucking or spitting oil out on the open road will immediately spoil a good highway cruise. Premium gaskets from sources such as Fel-Pro are worth the added price, as the hemorrhaged gaskets shown here woefully attest. When cylinder pressure gets more serious from compression, nitrous, or blowers, think about moving up from OE replacement-grade head gaskets to wire-reinforced premium head gaskets from Mopar Performance or Fel-Pro. O-rings are probably a good idea if you're heading for the twilight zone in horsepower generation.
6. Ratio Realism
No doubt for the digs, you either go low with the rear gears or go slow at the green light. On the open highway, though, those 4.56s will leave you eating parts, literally winding up to ruin. The cruiser concept is to build low-end torque up front and gear-up in back; on the open road, trashing those 3.23s for 4.10-plus killer cogs is the wrong move.
7. Freshen It
Mopar drivetrains and trannys were the toughest in the industry, but for street survival 30 or more years later, it pays to start fresh. When rebuilding an old Mopar, it's tempting to just clean up major components, bolt them in, and hit the road. However, even if major components, such as the transmission or rear, are functional, they may be about ready to fold, depending on the mileage or the abuse. To keep them in the game often, all that's required are new bearings, races, seals, and gaskets, with the other hard parts simply cleaned, inspected, and usually reused. Here, we have a four-speed kit from Brewer's ready to go in. Some new bearings now can save lunching a hard-to-find or expensive gear cluster later. Same with syncros; step up with fresh brass and save those dog teeth on the main-drive gears. We swapped a junkyard overdrive 833 in our Dart, only to find the first-gear syncro was boned out. Lesson: It pays to go through it first rather than do the job twice or find yourself stranded.
8. Overdrive Options
For highway starring, stepping up the gear (lower numerically) is a good idea, but for some, giving up that righteous off-the-line dig is unacceptable. While all of the old Mopar musclecars were 1:1 at the tranny, swapping to an overdrive can open the best of both worlds. Automatic cars can use the Mopar 518 overdrive or keep the 727 by adding a Gear Vendors overdrive. Stick machines can choose from low-buck factory 833 OD trannys for an easy bolt-in swap or move to an aftermarket trans, such as the high-end Richmond six-speed pictured above.
We like the flexibility of the OD option, but don't forget, the driveshaft speed is still dictated by the ring-and-pinion. The wide-ratio factory four-speed overdrive has an extra-low 3.09:1 first cog, with a sprawling leap between each speed, and it needs mods to live under serious torque. Though automatic overdrives or aftermarket gearboxes take fabrication to install, the OD may be the best modification a road-going Mopar can get, depending upon your intended use.
9. Driveline Dynamics
Look at an automotive driveshaft next to an injected Hemi or a cross-rammed big-block, then walk around back and check out those massive meats, and you've gotta wonder how that stick lives in between them. For the street driver, the driveshaft needs to be tough enough to take whatever level of abuse is tossed at it and smooth enough to be imperceptible on the road. Getting it right starts with having a level of beef that's up for the application. Most Mopars came with either 7260- or 7290-series U-joints, with the latter being the larger style used in factory H/D or HP cars. The smaller 7260 was generally used with six-cylinder or smaller and low-performance V8 applications. For performance applications, the 7290 is the one to use, since it handles more torque and lasts longer. Yokes are available for most rear-end and tranny applications to run the larger U-joint, if the vehicle wasn't originally so equipped. There was an even heavier duty U-joint used in some Hemi/Dana applications and with the Imperial "constant velocity" shafts, the 1330. Whatever joint type is used, the key here is to use only premium replacement joints, rather than be suckered in by the low price of weak imported units (your lack of towing bills in this area will more than make up the difference).
Beyond having U-joints up to the job, three other factors have to be correct: balance, phasing, and angle. Production balance was adequate for lower speed passenger-car duty. However, if performance modifications are done or higher driveline speeds are anticipated, it pays to have the driveshaft professionally dynamically balanced. Phasing is not an issue except in the actual construction of the shaft and relates to the alignment of the yoke eyes, and thus, the U-joints at each end. Getting smooth operation for road use relies on having the driveshaft (balance and phase) and the driven angles (the tranny and rear-end pinion centerlines, respectively) at specification. The factory service manuals for Mopar passenger cars have the specs. Adjustment is also outlined in the service manual, and remember that altering the angle for dragstrip use will come with a price in terms of open-road smoothness. Trick aftermarket aluminum and even carbon-fiber driveshafts can be bought, and they are often smoother at high speed than the stock steel shafts but are usually pricey.
10. BTU Blowout
Heat is the enemy of mechanical or hydraulic components, and it pays to dissipate heat, especially when specific modifications increase component heat loads. For example, a high-stall torque converter that generates more heat through increased slippage. Oil cooler systems are available to combat added heat, with the finest factory example being the late '70s B-Body Monaco and Fury Police Interceptors, which came rigged with rugged and efficient coolers for the trannys, the power steering, and the engine oil. Aftermarket sources can cover these applications as well and offer systems to cool high-winding rear axles. Do you need them? That depends on how the car is driven and what kind of modifications have been performed. Here's a B&M tranny cooler on a high-stall-equipped B-Body. For desert banzai runs, don't consider running without them.
11. Think Big
Mega-power under the hood needs to be balanced with mega braking behind the wheels. Brakes are one of the areas where bigger is always better, and there is a wide range of help available for older Mopars. Those '60s and '70s Mopars, especially the lower performance versions, often came with brakes that aren't up to par today, and a great percentage of the old Mopars built for the street these days began life as bread-and-butter, low-performance cars. That old Slant Six Duster may be a hot street machine with the infusion of a 380hp crate small-block-but with the stock brakes, it's a death trap. A variety of approaches can be taken to up the ante on stopping power, running the gambit from retro-fitting, bigger OE brake parts, to pulling out the stops and forking over for a race-derived, four-piston-caliper, four-wheel-disc system. The choice is yours, and in this iinstance, your decisions should first be made on what you need, then on what you can afford.
12. Yes, Master
All the brake at the wheel is worthless if the master cylinder hanging on the firewall won't squeeze the juice. Experience tells us that the dirt-cheap reman masters from the corner parts emporium are a crapshoot. A better bet for OE-style rebuilt masters are specialists in the hobby market, such as Master Power, shown here. Mopar Performance has conversion kits available to bolt up new, later-style Mopar aluminum masters in place of the cast-iron originals. Any mid-'60s-or-earlier single-reservoir Mopar should be retrofitted to a safer, dual-master system for real street use. Ever pop a wheel cylinder on a single-master system? We have, and the instant no-pedal at speed on a busy street was instant crisis. Luckily, we avoided disaster, but we learned a close lesson we won't soon forget.
13. Power Pad
Drum brakes not only rust, but also fade away; nothing like trying to slow down your worked B-Body and finding that the drums have gotten too warm to work efficiently. Luckily, Mopar aftermarket growth in the '90s provided disc brake conversions. Once installed, the stopper will stop when called upon, not when they decide to. Use quality pads; some such as these from EBC also created to prevent rotor wear and grind. There are even pads available that are constructed from carbon fiber for even greater heat dissipation and longer life. Regardless, unless you are doing a full-tilt restoration, front disc brakes can be the best upgrade to your vintage Mopar. For serious street-strip cars, four-wheel outfits may be an even better bet.
14. Line Me Up
Hitting the streets with 30-year-old, rusty steel brake lines and cracked, bulged brake hoses is way too whacked-out for us; Why, why, why? when the aftermarket has new line kits available for most older Mopars, which means you don't even have to fab your own anymore? Lines are available in stainless, which look good and should outlast anything else on the car. We picked up this set from Penstar Reproductions at a local show. Don't sacrifice your Detroit iron by deciding the worn-out stuff is "good enough," because it isn't.
Here is one we all know and love but needs repeating: the good old Mopar electronic ignition. Does it work? Millions of production vehicles have answered that beyond debate. Is it the hot ticket on my street Mopar? Consider the fact that any part of the system can be bought at the counter of virtually any auto parts store across the country. Mighty reassuring when you're a long way from home. Is it good enough for my stout street car? We've turned 7,000-plus rpm on the street and the dyno, and it works as well as anything else running the low-buck street Mopar Performance system. Racers across the country run the system with MP's race control boxes, proving it every day. For real street, it's the best thing going. If you still have a points ignition, you just must like tinkering on a regular basis.
16. The Terminator
Though a lot of guys don't like working on it, once in a while we have to mess around with the wiring on our Mopars. For real street use, reliability is the key, so here's the real deal. Get rid of the cheap crimp connectors and use OE-style, noninsulated terminals. Use a pro-type crimper tool, which folds over the crimp tabs and indents the solid backing of the terminal for an OE-quality crimp. Once crimped, drop a bead of solder in the connection and you've got a terminal that won't fail. Use OE-style insulating cases and connectors or, minimally, some heat-shrink tubing. The worst approach is using cheap insulated aftermarket terminals crimped with nasty low-buck crimpers that just squeeze the terminal. These connections start out poor and will usually fail in time.
17. Connector Conductivity
A sound electrical connection is with minimal resistance. This means a good mechanical fit and no corrosion. Unfortunately, given all the years since they were new, corrosion on terminals is all too common on old Mopars. What to do? A dip in a mild acid solution, such as PPG's Metal Prep will quickly dissolve the corrosion, restoring the conductivity of the connection. Rinse the cleaned terminal with water, dry, and hit it with some WD-40 to protect the bare metal. A dab of dielectric grease will protect the connection practically forever.
No Fuelin' Around
18. Cool Fuel
We all know fuel octane is down from the good old days, but it seems today's fuel is more sensitive to heat than the stuff that was around when 'Cudas were new. Fuel-injected cars, with their high-pressure fuel systems, are largely immune to the problems of fuel percolation, vapor lock, and gasoline boiling in the carb's bowls during hot soak. This unfortunate problem is ugliest with aluminum carbs, the material used to make our Mopar's old Carter AFB and AVS mixers.
What to do? First, use a thick, heat-insulating gasket between the carb and the intake, which was OE on most Mopars. If an aluminum manifold is used, particularly in hot climates, block or restrict the exhaust crossover. Finally, make sure you use a fuel return line, which circulates excess fuel capacity back to the tank, allowing cooler fuel from the tank to continuously circulate back up to the carb. Many factory high-performance cars had return lines stock. This system can be retrofitted into standard cars, or a system can be fabricated using a fuel filter with a return fitting and running a steel line back to the tank.
19. Pressure Point
Without fuel getting to the carb, you're dead in the water. Factory HP cars used a 3/8-inch fuel line versus 5/16-inch lines in lesser models. The fatter fuel system is being re-popped by aftermarket line makers, so why not upgrade? Even with the good lines, the pump has to deliver the fire-juice, and again, the factory used special pumps in hi-po applications. Get the good pumps if running mechanicals; both Holley and Carter make new pumps similar to the factory performance units. Verify the fuel pressure with a mechanical gauge, such as this online unit on David Frieburger's Duster. For long treks, consider an electric pump near the tank. Not only will it help prevent vapor lock, but it can save your butt if the mechanical piece fails.
Cool it, Dude
Nothing's worse than puking green Prestone on hot tarmac, sweating with the heater on in 100 degree heat, and trying to coax the needle on your Stewart Warner temp gauge back down to safe, all the while trapped in the sprawl of urban traffic. It happens all too often. Got a big Mopar mill? You need a serious cooling system to chill that bad boy. Start with the radiator. If heating's a problem, get the largest radiator that fits your Mopar body style. Still not enough? Go four row. Yeah, we've heard the same bogus spiel, "The air gets hotter as it goes though, so the extra rows don't help that much, blah, blah, blah." Get a good, four-row, high-efficiency core, and watch the temperature drop. You can usually use the OE tanks, brackets, and shroud; any good radiator shop should be able to hook you up.
Always run a shroud (available repopped from the usual resto sources) and finish the system with a serious viscous fan. Run the biggest fan that will fit (most OE units interchange), and mate it with a good, new, thermostatic clutch, rather than the cheaper viscous drive. Other key players for problem coolers are a balanced-flow thermostat (sometimes they really help), available from Milodon. Want more? Milodon, Edelbrock, and others carry high-flow water pumps, and aftermarket aluminum radiators are available in high capacities, but check the rating before buying. This Dart has been fitted with a 26-inch radiator, which runs framerail to framerail; a factory shroud; and a huge seven-blade thermostatic clutch fan assembly.