Small rod journals equal lower...
Small rod journals equal lower bearing speeds and reduced rotational weight in both the crankshaft and the rod. Because of the lower power levels produced, Mini-Stock engines can reliably use Honda-size rod journals to create power without significantly reducing durability.
The Nextel Cup guys have been using Honda-sized rod journals for years. By cutting the rod journal down to a 1.888-inch diameter, the bearing speed is significantly reduced. This cuts friction in the engine, freeing up horsepower. Smaller journals also cut weight in both the crankshaft and connecting rods, and a few ounces shaved off the rotating assembly at each cylinder adds up.
Honda journals haven't really caught on among the V-8 classes in Saturday night racing, however, because the significant reduction in journal diameter (a Chevrolet rod journal, for example, is 2.100 inches) harms engine longevity. Unlike the Cup Series, Saturday night race teams simply cannot afford to sacrifice an entire engine for the sake of a couple of extra horsepower.
But in Mini-Stock racing horsepower usually tops out at just under 200, a level that 1.888-inch rod journals are more than capable of handling. Stock crankshafts are almost always reused in the build, and they will have to be turned down anyway to clean up wear from miles of road use, so turning the journals down to Honda diameter doesn't incur big cost increases. Running a Honda journal does, however, require a little extra money when purchasing your rods because they are a specialty item.
Dan Esslinger says Esslinger...
Dan Esslinger says Esslinger Engineering's aluminum cylinder head for Ford 2300 engines is designed to be just a little better out of the box than a fully ported stock head. This means that while the head is more expensive than pulling a stock Ford head out of the junkyard, it does offer savings over trying to make a high-end race head out of the stock piece.
Just a few years ago there were no conversations about using aftermarket cylinder heads for Ford Mini-Stock racers. That's because there weren't any available. But Esslinger Engineering recently came out with an aluminum stock replacement head that offers a serious performance advantage over the stock design. Many Mini-Stock racing classes do not allow this head yet, but Esslinger says it has been catching on because, while Ford 2300 blocks are still plentiful, cylinder heads are becoming increasingly scarce because they are prone to cracking.
Keep an eye on this development. Esslinger's aluminum cylinder head isn't established in Mini-Stock racing yet, but it is probably only a matter of time.
This hose where the oil-fill...
This hose where the oil-fill cap normally is found connects to the exhaust header just below the merge collector. The exhaust pulses can help create vacuum inside the engine crankcase, freeing up power.
It is a trick that drag racers have been using for years, and in upper-level racing classes it often is specifically disallowed. But using the exhaust to pull vacuum in the engine is a trick that usually isn't mentioned in the Mini-Stock rule books. Just like a well-designed exhaust header utilizes exhaust pulses to help pull spent combustion gasses from the cylinders, you can use the headers to help draw a small amount of vacuum inside the crankcase. In the Ford 2300 engine the crankcase vent tends to catch a lot of oil, so many racers route a hose from the crankcase vent to the valve cover. But Johnson's Machine Shop, which specializes in four-cylinder Fords, routed a hose from the valve cover to the exhaust header just below the merge collector. The low-pressure pulses inside the header draw air from inside the engine, acting like a vacuum system.
Johnson's also added an anti-backfire valve off of an old Chrysler to keep anything from coming back into the valve cover. This trick works, but just be aware that at high rpms you can get an oil mist sucked into the manifold, making the car smoke. But, hey, that may make your competitors think you are running a race engine on its last legs and underestimate you.
These rockers have the wear...
These rockers have the wear pads covered with machinist's dye because they are about to be checked to make sure the cam's lobes ride over the middle of the pads. In high-performance situations standard rockers won't hold up to aggressive cam designs, so aftermarket rockers with hardened wear pads should be used.
This tip has more to do with longevity than power, but it is still important. Remember earlier how we mentioned nitriding your camshaft to protect it? Well, the aggressive cam designs used in Mini-Stock race engines are also hard on the rockers. Fortunately, the solution for this is simple. Many engine builders, including KT Engine Development, use and sell rockers with hardened wear pads. Standard pads will grind off slowly, which not only puts metal into the oiling system but can change the valve timing events.
Unibody cars, such as the...
Unibody cars, such as the Mustang (shown here) and Toyota Celica are notorious for their flexibility. Intelligently bracing the suspension will make sure your suspension settings stay accurate on the racetrack.
One of the problems with racing a stock-based chassis in any class is undetected flex can wreak havoc with your chassis settings. Stock chassis are designed for safety (crumple zones), ease of manufacture (cost) and minimum weight (gas mileage). None of those factors are necessarily helpful when it comes to resisting the g-forces a chassis will see as it powers through the turns on the racetrack.
Flex means those chassis settings such as caster, camber, toe and even frame heights that you worked so hard to set precisely can change on the racetrack without your control. Use the front and rear kickouts on your rollcage to help brace the suspension. At minimum, you should have hoops welded over the upper shock/strut mounts. Also consider additional bracing that extends to the ends of the front and rear sections of the chassis to limit twist.