Ford-powered cars have made tremendous strides in short-track racing with many titles on p
Make a visit to any Saturday night racetrack across the country-it doesn't matter whether it's asphalt or dirt-and take a survey of the brands circling the racing surfaces. Chances are the Bow Tie Brigade is going to greatly outnumber the ambassadors of the Blue Oval in the V-8 classes. There is no doubt Chevrolet enjoys an advantage because its design for the small-block V-8 has been in so many cars over a span of 50 years. It's a tried-and-true design that plenty of people are comfortable building and working on, but it doesn't make Ford's Windsor V-8 a slouch
The fact is Ford's small-block V-8 has a few distinct advantages over its Chevrolet counterpart. Take, for instance, Ford's higher camshaft location that allows for a greater stroke before you hear the dreaded clang of the rod bolt hitting the camshaft. Of course, most of these improvements are the result of Ford reverse-engineering much of Chevrolet's V-8 because it was on the market first and readily available for inspection-but an advantage is an advantage.
Ford's cam journals are already a sizeable 2.035 inches at the smallest hole. This is sign
Make no mistake, Circle Track is a fan of torque and horsepower, not badging. But, in the interest of fair play for everyone, we thought it might be a good idea to share a few power tips for the Ford minority. To do that, we polled some of the most respected Ford engine builders and component designers in the industry. Larry Clark builds Scott Bloomquist's all-aluminum torque monsters for Dirt Late Model racing. Joe Rhyne is the man who provided the power for Frank Kimmel's three-straight ARCA championships. You get the idea. Just do us one favor: The next time you go out and kick a Chevrolet's rear end, don't give us too much credit.
Big Cam Bearings
One of the positives for Ford blocks is the big cam bearings they run. You don't have to worry about camshaft deflection on a Ford like you do on a stock Chevy block because the Ford comes with cam journals that are nearly two-tenths of an inch bigger than a Chevrolet. The cam bearing that we always look at on a block is the next to last-that's the smallest that you have to fit your cam lobes through. On a Ford, that hole is 2.035 inches. On a small-block Chevy, it is 1.869 inches. That's even bigger than a 50mm Chevy. Plus, the Ford block can easily be line-bored to 2.065 inches. The bigger camshaft barrel diameter not only means a stiffer overall cam, it also allows for a bigger base circle. With a bigger base circle, you can spread the lobes out. On a flat-tappet cam, that means you don't exert as much stress on the nose. On a roller cam, it allows you to reduce the pressure angles on the rollers. Overall, it's just better.Mike JonesUltra Pro Racing Cams704/392-1715
Flatter can be Better
Ford's N351 and N352 cast-iron heads have a shallow, 10-degree valve angle. If you are running a class that doesn't have a compression rule, you can really take advantage of this. The shallow valve angle means you need a smaller valve pocket in the tops of the pistons. You can really cut down the deck of the head and cut that combustion chamber way down before you have to cut too much of a valve pocket in the pistons. The limiting factor for any valve pocket is the thickness of the aluminum in the top of the piston. You don't want too much material there because it will make the piston too heavy, but a relatively thin piston top limits how deep you can cut the valve pocket. The Ford's shallow valve angle means you can deck the head a lot more than a Chevrolet 23-degree head without changing the valve pocket significantly. The resulting gain in compression ratio can be a big advantage.Kevin TroutmanKT Engine Development704/784-2610www.ktengines.com
Ford's cast-iron racing heads, the N351 and N352 models, feature raised ports with good fl
Go with the Good Stuff It used to be that when you went to build an engine for your race car, you didn't have much choice except to start with an old production street block. Our demands for a good race block have advanced to the point that it's just no longer reasonable. Ford Racing and other manufacturers have produced blocks specifically for racing that give us a lot more of what we need in a race engine. Put it all together, and a junkyard block may sound cheap in the beginning, but it is really more money after you put in all the time and effort to bring it up to spec. Ford and some of the other manufacturers have done a really good job of bringing what's normally called a Sportsman block to the plate. It isn't as expensive as a Nextel Cup block, but it offers a lot of the same advantages.
Besides Ford, Dart also makes a good Sportsman block. To begin with, Dart's block can be built as either a wet- or dry-sump engine. These blocks are also cast from better material, and core shift is minimized. On the Dart block, I know that the oil galleries have also been revised. In a dry-sump application, you can oil the thing from the front, the rear, or both. When you oil from both the front and the rear, you can actually cut your oil pressure back tremendously. That's obviously an advantage in terms of power because when you run less oil pressure and still keep proper lubrication, it saves you horsepower.
No matter what Ford block we use, we still spend a good bit of time with each one to lighten it up. If a person is weight conscious, you can lighten just about any block. Some areas from which we get the most weight are the bellhousing area of the block and, if you are running a dry-sump, the filter boss. Internally, in the area where the oil pump would normally go, we remove all that material. There are many other areas where you can trim down and thin out a little. We can get 15 pounds off of one of those blocks without getting close to water or oil galleries-it's not too much trouble at all.Joe RhyneRhyne Competition Engines219/845-1218
It may be tempting to try to save a little money up front, but Ford's Sportsman block, and
Go Easy on the Gears
Be careful with high-volume oil pumps if you're running a wet-sump engine. A high-volume oil pump requires more power to turn, and that can put a real load on your distributor gear. You can wipe out a Ford distributor gear quite easily if you aren't careful or if the cam gear and the distributor gear don't mesh properly. If you determine that you need to run a high-volume oil pump, there are a couple of outfits out there that offer quality high-volume oil pumps for racing. Those companies have done some work to the Ford geroter pump and significantly reduced the amount of horsepower it takes to turn one, which will help the life span of the distributor gear.Jeff KlaverFord Racing586/468-1356www.fordracing.com/performanceparts
Know Your Flow
Your camshaft doesn't care what label is on the valve covers. It really doesn't perceive whether it's going in a Ford or a Chevy, but what it does perceive are things like port size and shape and valve size. It's hard to make global generalizations when it comes to building Ford engines because there are so many options available, but we can do some things with specific cylinder heads.
If you are racing cast-iron heads, Ford's N series of heads (N351 and N352) are pretty good pieces. They have raised exhaust ports that flow well, and the camshaft durations between the intake and exhaust should be relatively close.
If you run a wet-sump engine and need the additional oil pressure that can only be provide
When trying to match a camshaft to a set of heads like this, it is important to know the amount of flow differential between the intake and exhaust ports. For example, let's say you have a traditional Yates head that flows 400 cfm in the intakes and 250 on the exhaust. If you divide the exhaust number by the intake's flow, you get 62.5. Exhaust flow is 62.5 percent of the intake flow, so we call that a 62.5 percent head. Chevrolet's 18-degree head has a real good exhaust port, so in most applications, you would not have much more exhaust lobe duration on the cam than you would on intake duration. It is usually around 4 to 6 degrees, and no more than 8. Sometimes, you can even run a straight pattern on a cylinder head such as this.
It's exactly the opposite with a lot of stock Ford castings that don't flow much better than 50 to 65 percent exhaust-to-intake. On something like that, in order to get the exhaust out of the cylinder, you might need the exhaust lobe duration to be 8 to 12 degrees longer than the intake.
Of course, a high-flow exhaust port isn't the primary determining factor when it comes to building power in a race engine. Compare the 18-degree Chevy cylinder head to a Yates Ford head when it first came out. The Chevy head's intake port isn't as good, but its exhaust is far superior. On the Chevy, the durations are very close to each other-typically 260/264 (intake-to-exhaust) on a low-rpm engine and 270/274 on a higher-rpm application. The splits are usually 2 to 6 degrees. The traditional Yates head needs about 12 more degrees on the exhaust than the intake. The exhaust port doesn't flow nearly as well, but you can make up for that somewhat with more exhaust lobe duration. But the results on the track proved that the Yates head was superior, and Chevrolet was forced to redesign its cylinder heads and come up with the SB2.
Canted-valve heads are more efficient in high-rpm applications because the valves are angl
A lot of people say that a 75 percent cylinder head is the perfect balance. That's a good guideline but not necessarily true for all applications. Generally, an 85 percent head needs 6 degrees more exhaust than intake. As that number increases to 90 percent, the split drops down to nothing. If the percentage drops to 50, you wind up with about 20 degrees more exhaust lobe duration than intake. Your OE Ford heads are in the 60 percent range. The R-type heads are in the mid-to-high 70s, and your Yates head is back down in the 60s. Those numbers don't necessarily determine engine power, but they do help you predict what cam you will need to make them run best. The best heads on the market are clearly developed around the intake port. When the intake is perfected, the best possible exhaust port is designed with what is left.Billy GodboldCompetition Cams800/999-0853www.compcams.com
If you're running a steel-ring gasket that doesn't have much crush, you may want to adjust how you torque your head bolts. This is especially true if you are running cast-iron heads. The new gaskets with steel rings have very little to no crush, and that can lead to cracks in the head if too much torque is applied. The inner row of head bolts will need more torque than the outer row, or the bolts closest to the exhaust. I cannot give you exact figures because there are too many variables involved, but you want at least a 15 ft-lb difference between the intake row of head bolts and the exhaust row. Without this difference, you can bend the exhaust flange of the head, which will result in a crack. That split in torque numbers might not need to be as big if you are running a cheaper head bolt, but on premium ARP-type bolts you want at least that much difference. Because Fords only have 10 head bolts, you probably will want to run a premium fastener anyway.Jeff KlaverFord Racing 586/468-1356www.fordracing.com/performanceparts
Just because Fords are the minority in almost every racing class, doesn't mean the engines
NASCAR has just accepted a raised-port, canted-valve head for the Nextel Cup guys, but we've been racing a version of that in Dirt Late Models for some time now. We are starting our third year with canted-valve heads on Ford engines, and they have definite advantages. We are lucky in Late Model dirt racing where the rules are not very restrictive and we have the freedom to do what we want.
Canted-valve heads aren't a major power gain for the engines in the bottom and middle rpm ranges, but they do run quite a bit harder up high. The reason for this is quite simple: The canted-valve design angles the valves away from the cylinder walls, which improves flow at high-valve lift. This doesn't make much difference at lower rpm levels because the slower engine speed allows enough time to completely fill the combustion chamber. When you get above 8,000 rpm, conventional heads start having difficulty filling the chambers. The canted valves reduce shrouding against the chamber walls and improve flow in the upper rpm ranges.
You can't see any difference between canted-valve heads and conventional heads until you get the motor revved up above 8,000 rpm, and the higher you get above that, the better the head gets. If you look at a 410ci motor, at 8,500 rpm, the canted-valve head offers a pretty significant gain. It improves the power by approximately 25 hp. But if you compare the heads on the same 410 engine at 7,000 rpm, it's minimal. The canted-valve head is only starting to come on at that point.
If you're looking into running these heads, the biggest concern is added weight in the valvetrain. The valves are angled into the combustion chamber, which means the stems are longer. Try to make things as light as you can, and also run a cam profile that you know will allow the engine to rev up. Still, the extra weight of the valves means you have to be careful to keep everything in control. We put the entire valvetrain package on a spin fixture and run it up so that we know at what rpm there will be trouble with a certain configuration. Smart decisions are a must when it comes to lobe design.Larry ClarkCustom Race Engines865/573-1449
Oil Showers They aren't specific to Fords, but valve cover oilers are a good idea anytime you're pushing an engine to its limits. The oilers are spray bars in the valve covers that spray a mist of oil onto the rocker arms and valvesprings. This helps reduce friction and keeps the valvesprings cooler. Heat in the springs is a big contributor to spring failure, and the oil really helps this matter. Normally, valve cover oilers are used with dry-sump engines, which also makes them easy to plumb. With a dry-sump, you just use a tee fitting from an oil supply line and feed it into the inlet on the valve cover. After the oil sprays on to the valvesprings and rocker arms, it drains back to the pickups via the normal path. You need more oil volume and will perhaps need to spin your oil pump a little faster to keep up with the added demand.Don LositoUltra Pro Machine704/392-9955
If you are running a flat-tappet cam, the Ford block has a definite advantage over Chevrolet. Ford's lifter bores are 0.875 inch. With a flat-tappet cam, the bigger the lifter, the greater the velocity it can withstand before the sides start digging into the lobe of the camshaft. On a stock Chevrolet with a flat tappet, you are limited to a velocity of about 0.007 inch per degree of rotation. Because a Ford's lifter bore is larger, you can get to almost 0.0075 in terms of lift velocity. That extra velocity means you can open the valves in the combustion chamber that much quicker. A lot of dirt racing series require you to run stock lifter bores, so in a Ford, this can be a real advantage.Billy GodboldCompetition Cams800/999-0853www.compcams.com