Auto Performance FAQ (Part 1)

Over the years, Jon and I have received a large number of questions that were submitted by readers of this and another automotive blog we run. Here are some questions and answers that we feel would be beneficial to our readers.

Once you’re done reading these, check out part 2 of our FAQ.

WHAT’S BETTER, A BODY LIFT OR A CHASSIS LIFT?

What’s better depends on what end-result you desire. Some owners want to go as high as they can, so they do both. Years ago, chassis lifts were the norm as many body lift manufacturers did not include new bumper brackets and steering shaft alignment linkage. But not so today with Performance Accessories. A chassis lift directs the driveshaft at a larger angle which can sometimes increase U-joint wear. A front chassis lift can also require new raised spindles and it can also eliminate some of the suspension travel. This reader simply wanted three more inches of wheel well clearance while keeping his stock suspension and ride quality, so Performance Accessories Body Lift Kit was the way to go.

WITH THE BODY THREE INCHES HIGHER, IS THE STEERING COLUMN AND STEERING WHEEL NOW THREE INCHES LOWER?

Nope. Years ago, you had to lower the steering column at the firewall to align it at a deeper angle to the steering box but not today with Performance Accessories’ kit. As we’ve shown, an extension slides over the steering shaft then connects to the steering box. Done deal.

I HAVE NO HOIST. HOW DO I JACK UP THE TRUCK BODY?

You could call Performance Accessories and ask for an installation dealer nearest you – where you can buy their Body Lift Kit and have it installed professionally. Or if you want to do it yourself, start by calling their customer service representatives or just buy the kit reading the instructions. The job could be done with a few floor jacks. Because they usually do not lift high enough, some 4×4 wooden extensions would be needed.

NOTE: Floor jacks have a “cup” housing on top. A wooden extension may not always sit flush and therefore it might be prone to angling or tipping. Remedy: lay a 3/8-inch to 1/2-inch thick square piece of steel plate atop the cup to “level the playing field”.

IF THE BODY IS THREE INCHES ABOVE THE FRAME, WON’T THERE BE A BIG GAP ABOVE BOTH BUMPERS?

No, there won’t. Included in the Performance Accessories’ Body Lift Kit are gold anodized bumper brackets that bolt to the top of the frame then to the bumper. Tah-dah! Both bumpers are exactly where they should be in relationship to the body. It all looks stock – just three inches higher.

ARE ANY BUMPER MODIFICATIONS NECESSARY?

Due to the height size of the front frame horns, the bumper’s integral plastic valance had to be ever-so-slightly trimmed for bumper clearance. A hand-held electric jigsaw or grinder does the job nicely.

WHAT HAS TO BE DONE TO THE GAS TANK FILLER HOSE?

Because the gas tank stays as-is but the filler door and hose raises three inches, Performance Accessories has included in its kit a superb hose extension to keep everything status-quo.

WHAT’S BETTER, BUYING ENGINE UPGRADE PARTS ONE AT A TIME OR IN KIT-FORM?

There are many answers. Here are a few to consider: With a large company like Holley, you can go either way. Many buy these upgrades one at a time for financial reasons while others do it because they aren’t quite sure what they want or how powerful they want their vehicle, so they leave it up to the manufacturer. As for today’s engine performance upgrade kits like Holley’s Hot Street Avenger Performance packages, you do not have to be the world’s foremost authority on anything because they have done all the research and testing so there are no disappointments.

Buying in kit-form also has the potential for being cheaper in total cost. By seeing what Holley’s three stages of Hot Street Avenger Performance did a stock 454, we would definitely go that route.

HOW DOES DYNO TESTING FOR “REAR WHEEL HORSEPOWER” EQUATE TO ACTUALLY DRIVING THE VEHICLE ON THE STREET?

First, rear wheel horsepower is what’s truly moving the vehicle from stop light to stop light. It may never catch on the same way that gross horsepower at the flywheel has, but for the serious enthusiast or racer, rear wheel horsepower means everything.

Also, a chassis dynamometer lets anyone “test” virtually at-will new engine and driveline modifications for horsepower gains or losses. Best of all, you don’t have to pull the engine out of the car to see what power it has.

HOW MUCH HORSEPOWER DOES A TYPICAL DRIVELINE CONSUME?

Well, it depends. A front wheel drive econo car with a narrow-gear transaxle may consume less horsepower than say the heavy duty driveline of a high performance V8. Automatic transmissions without a torque converter lock-up don’t actually use up more horsepower; it just can’t transmit it all due to slippage (number of internal fins and overall diameter).

So, the answer generally can range from 20-30 percent for a manual transmission and 25-40 percent for a V8 driveline.

SHOULD I PAY ATTENTION TO MY ENGINE’S COOLANT WHEN RUNNING ALUMINUM HEADS, INTAKE MANIFOLD AND WATER PUMP?

Today’s aluminum heads, intake manifold and water pump is made from superior/harder alloy, compared to the past. Electrolysis (the eating of aluminum by the coolant over time) is not nearly as critical as it was 30 years ago. A coolant’s ability to transmit heat and lubricate with zero acidity has also increased.

So, pay attention to the component manufacturer’s instructions or recommendations. If there are none you can find, call their technical service department for advice. Also, read the labels and fine print on all of the top brand coolants – then choose accordingly.

DO I TORQUE MY ALUMINUM INTAKE MANIFOLD TO MY NEW ALUMINUM HEADS THE SAME AS TO MY OLD CAST IRON HEADS?

For some reason, guys tend to mis-torque their V8’s intake manifold bolts. There should be a torque spec card in the box. First, pros recommend brand new intake manifold bolts – coated with antiseize compound. For the record, intake manifold bolts call for a torque-spec to aluminum heads of 25 foot pounds. (Iron heads are 30.)

WHAT ABOUT ALUMINUM HEAD SPARK PLUG TORQUE SPEC?

According to the General, big-block aluminum heads with flat gasket spark plugs call for 25 foot pounds with anti-seize on the threads. Tapered seat spark plugs call for 15 foot pounds with anti-seize. (FYI: Cast iron heads require no anti-seize compound).

HOW MUCH TORQUE DO STEEL HEADER BOLTS REQUIRE IN ALUMINUM HEADS?

The General says 20 foot pounds – with anti-seize compound on the threads. (FYI: Iron heads are 25 with anti-seize compound.)

I PLAN TO RUN MY ALUMINUM HEAD 454 AT THE DRAGS. SHOULD I KEEP THE ENGINE COOL OR HOT?

Speaking from past experience, warm the engine to normal operating temperature. You may find after a run or two that you can increase the total timing because aluminum heads are so much more efficient in the heat transmission department. Because they transmit heat so much better – when they’re cold, power is down. Cast iron heads do not transmit heat as well, so racers like to keep them cooler.

Also, when aluminum heads are cold, there is a chance they can “walk around” a little during full throttle causing coolant leakage. When at normal operating temperature, their expansion rate is more than that of cast iron so they are locked in position and ready to perform.

FOR MORE V8 PERFORMANCE, WHERE IS A GOOD PLACE TO START?

If we were sitting down having a cup of coffee, this is what we’d say – based solely on past experience:

  1. Start with the exhaust system. By doing so, you will maximize the stock V8 as-is powerplant. Make sure the muffler is as free flowing as possible without being so loud that it rattles your neighbor’s windows when you drive by.
  2. Make sure there are no neck-downs and pancakes within the exhaust system’s pipes. There usually are, so expect to install a good aftermarket cat-back exhaust system. Most feature mandrel-bent pipe (no neck-downs).
  3. Consider a good set of thick wall (16 gauge) tubular headers. For part- and full-throttle torque production, the longer the header primary pipes and collectors are, the better. Headers aid exhaust scavenging above fast-idle speed, say 1,500 rpm. Above this rpm, headers are more efficient than original cast iron manifolds, so you’ll be making more power on less gas.
  4. An exhaust crossover pipe located about 12 inches behind the header collectors sometimes lessens part-throttle torque production on lean-burn engines by a few foot pounds. This is due to balancing the exhaust gas pulses thus increasing scavenging of the spent gases. It also quiets the exhaust tone a few decibels too.

FOR MORE POWER ON A STOCK V8 WITH A GOOD EXHAUST SYSTEM, WHAT SHOULD I CONSIDER?

With a good free-flowing exhaust system, the next obvious place to make more V8 engine efficiency is the induction system: air filter, carburetor or fuel injection and intake manifold or F.I. runners. In a street-driven engine, increased performance comes through optimizing cylinder filling with air and fuel at both part-throttle, lower rpm as well as at full-throttle mid-range to top-rpm.

Seldom if ever is a factory air filter totally efficient. For today’s new vehicles, there are plenty of different (and legal) breathers assemblies – usually of the ram-air type. Cooler incoming air means a denser charge / more molecules….more power!

  • Fuel injection throttle bodies usually cannot be enriched, except in a few cases by increasing the fuel pressure.
  • Fuel enrichment is usually done by reprogramming the ECM (engine control module).
  • Lastly, the fuel injection’s runners can be replaced with bigger ones available in the aftermarket which aid breathing at higher rpm.

AFTER MAXIMIZING THE EXHAUST AND INDUCTION SYSTEMS, OVERALL POWER HAS INCREASED BY OVER 50%. WHERE DO I GO FROM HERE?

It all depends on what you are trying to accomplish. We would install a new torque-efficiency camshaft and aluminum heads. Others with different priorities may go with a hotter different cam and kit then bolt on a 150 horsepower nitrous oxide kit.

WHEN TWO CARS ARE SOUPED UP THE SAME BUT ONE IS 1/2 CAR-LENGTH QUICKER, WHY IS THIS?

Hey, sometimes it’s the driver that makes the difference. But if you switch cars and the faster car is still the fastest, it could be that one engine just sometimes seems to run better than the rest. How so? We call it “Super Tuning” and it’s our middle name. You just don’t bolt hot parts on and go!

Anyone growing up back in the sixties and seventies and paying attention to Stock, Super Stock and Modified Production drag racing eliminators knew that to win you had to be a dandy driver and an even dandier engine and driveline tuner. If you weren’t, you got trailered in the first round.

ARE THERE ANY LIMITATIONS ON ASSEMBLING A STREET ROD AT HOME?

This answer lies directly with the kit’s manufacturer. Most enthusiasts are masters at bolting things together. But not everyone owns, let’s say, a gas or electric welder. So, if any welding is needed, the buyer should be aware of this prior to purchase so a game plan on who’s going to do the welding can be formulated.

Other tools such as a quality floor jack, electric drill, flat and round files, wrenches and ratchet set, wiring kit, and so on are things one would certainly also need to have on hand.

HOW MUCH KNOWLEDGE / SKILL IS NEEDED TO DO THIS BUILDUP?

Knowledge and skill is nice but for the beginner, we feel patience is first and foremost. Through patience in learning comes skill and knowledge. The kit car comes with an assembly manual so anyone with a basic comprehension and interest in automobiles should be able to follow it with precision.

ARE THERE SPECIFIC “BENEFITS” FROM BUYING A STREET ROD KIT CAR?

You bet. First, buying an entire engineered car unassembled in pieces rather than buying separate components from various sources is almost always cheaper in cost. Second, the kit car companies’ customer service department is available for your every question. Third, the parts are engineered to fit. This is not to say that other brand–x parts won’t.

Let’s just say that if there is an “aggravation factor”, it will be greatly reduced. Believe it or not, a big problem for a beginner is remembering “body to frame fit”. All too often, the fiberglass body is bolted down prior to being centered. The end results are front and rear wheels that are not centered in the wheel wells.

CAN NON-KIT PARTS BE INTEGRATED?

As previously stated, kit cars are sold in a variety of ways. But if by chance they do not offer an accessory or item you prefer such as gauges or a certain type or style of air conditioning, you bet you can mix or match. The real key here is in the planning.

Absorb every item the kit car manufacturer offers – up to and including the taken for granted items such as the firewall, overall body length and height, etc. Few brand-x parts are of such a size or spec that they won’t fit. It pays to ask for a recommendation or opinion prior to purchasing non kit-car parts.

HOW MUCH HORSEPOWER DO I NEED?

Generally speaking, street rods are light and do not require much power to accelerate rapidly. Back in the ‘60s, a car with a power-to-weight ratio of 10 pounds per horsepower was considered fast. A 2,600 pound street rod with a 350 horsepower crate motor has a power-to-weight ratio of 7.43 pounds per horsepower.

FOR MORE POWER, WHAT’S THE FIRST ENGINE MOD TO MAKE?

While all engines can be thought of as air pumps – moving air in and out, some are more efficient than others are. High performance engines usually have a superior, better breathing exhaust system, therefore they may benefit more from a better breathing intake manifold, or for tuned-port fuel injection induction, better runners.

In a quest for optimum efficiency, a stock engine’s first job would be to optimize its exhaust flow potential then its overall induction potential, both at part- and full-throttle, from the air induction to the intake manifold. Next would be to optimize the overall ignition and distributor rate-of-advance or curve. Next would come the fuel system, namely the fuel pressure, fuel line diameter and performance filter.

Finally, we would make a camshaft and valve spring change, and we would street-port the heads for that extra bit of overall efficiency (and 40+ more horsepower).

WHEN IS PISTON-TO-VALVE CLEARANCE NECESSARY TO CHECK?

Most overhead valve, small-block V8 engines have a bit more piston-to-valve clearance than valve spring coil-bind clearance. Huh? In a small-block Chevy, its standard performance valve spring can work with a 0.470-inch lift camshaft before coil bind.

High performance, Z-28-type valve springs can go 0.490-inch lift. At 0.500-inch lift, coil bind will be ever so present. The engine won’t rev or make any power, and you may or may not pull rocker arm studs out of the heads. They may pull but not come all the way out.

All small-block Chevy V8s can usually get by with a 0.500-inch valve lift with no piston-to-valve clearance, intake or exhaust. This is for a cam installed “straight up” at 0 degrees before top dead center. If you advance it 2-4 degrees, piston-to-valve clearance checking with some putty is highly recommended.

Just for the record, most engines require on the order of 0.100-inch clearance on the exhaust valves and 0.080-inch on the intake valves. The extra clearance on the exhaust valves is because they get hotter and expand more.

CAN A ROLLER CAMSHAFT BE RUN ON THE STREET?

It depends on the cam’s grind, but sure! For decades, many have been dreaming of the day when a performance hydraulic roller camshaft would be conceived. For over three decades (1957-1987), the only roller camshaft available was a solid lifter grind – which necessitated periodic valve lash adjustments.

Back in the early eighties, various aftermarket companies began engineering a hydraulic roller lifter and camshaft. It took a while but it was finally brought to light and today most domestic V8 engines have a torque-type roller camshaft. Why? Less friction, better valve actuation for a longer period of time–meaning more torque and horsepower.

A roller cam in a high rev performance engine is something to behold. By comparison, with a flat tappet cam, at 6,500 rpm, it “feels” like the heads are going to explode off the engine. With a roller camshaft, the engine feels effortless, and there seems to be no valvetrain stress.

WHAT’S BETTER, A SINGLE-PLANE OR A DUAL-PLANE MANIFOLD?

All factory V8 engines have a dual-plane intake manifold because, by design, it helps produce more low rpm torque. Being more or less split in half, fuel and air velocity is increased at lower engine speed making for greater cylinder filling – hence more torque and horsepower output, all things considered.

Single-plane intake manifolds were originally engineered thirty years ago for dragsters and sprint cars that needed more mid-range and top-end power. The runners are straighter and more direct to the ports. The plenum is bigger and is one large area, compared to a dual-plane’s two smaller upper and lower areas.

If need be, more mid-range and bottom-end throttle response can be built into a smaller single-plane manifold by reducing its runner sizes, adding a plenum divider/wall right down the middle from front to rear and possibly raising the plenum floor height. Feel free to consult your favorite intake manifold technical service department for more on this subject.

CAN THE ACCESS ROLL-UP TONNEAU COVER BE INSTALLED BY ONE PERSON?

Sure, but it will take you a little longer to go through the simple installation steps.

I LIKED PUTCO’S “VIRTUAL” GRILLE FOR THE FORD SUPER DUTY F250. WHAT ELSE DO THEY MAKE?

As mentioned, Putco’s headquarters are in Story City, Iowa. You can reach them toll-free at 1-800-247-3974 or e-mail them at: info@putco.com. They make truck stainless steel running boards, fitted bed caps, tailgate guards, toolboxes and Locker side rails.

WHERE CAN I FIND OUT MORE ABOUT THE ACCESS TONNEAU COVER?

You can get more information by contacting their website, www.accesscover.com

IS COVERING POLISHED STAINLESS STEEL WITH WAX OR CLEANER A GOOD THING TO DO PRIOR TO INSTALLATION?

You bet. Even though polished stainless steel seems to last and last, giving it a coat of wax will make its shine last and LAST!

> Continue to Part 2 of our FAQ.

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