Stock Car Engines and Sanctioning Bodies: Different Groups, Different Rules - Engine Builder Magazine (2024)

But for engine builders, keeping up with these groups, and the many sets of rules, can be quite a task. How do you stay on top of what’s legal AND competitive? We will take a closer look at a number of groups that are off NASCAR’s beaten path and see what they have for rules.

There’s a lot going on with these groups, the rules and technical information may include different engine configurations, types of components allowed, claimer rules, horsepower limitations and the like. And there are also issues of fuel injection vs. carbs, FWD vs. RWD, trucks vs. cars; ovals vs. road courses, asphalt vs. dirt and more, to contend with.

The Automobile Racing Club of America (ARCA) is one of the oldest stock car groups, and they have been a well-known stepping stone to the NASCAR pro ranks. The cars are former Sprint Cup models that race on many of the same tracks as the big boys. However, within this description, the ARCA series is also one of the most varied series in stock car racing.

ARCA’s Don Radebaugh describes the Super Car Series as a very diverse racing series, typified by the Bill France Four Crown award, which exemplifies four very different types of tracks that ARCA competes on – Superspeedways, Short Tracks, Dirt Tracks and Road Courses.

The series uses full, steel bodied 3,400-lb. cars that are either Ford, Chevrolet, Dodge or Toyota. Engine rules are similar to NASCAR Sprint Cup Series. Engines are limited to 360 cid max with 12:1 compression. However, ARCA allows a roller cam whereas NASCAR does not.

Engine builders supplying ARCA teams are limited to a few specific rules. They cannot use aluminum blocks and have to use production made intakes only. Dry sump oiling is mandatory and only one 4-barrel carb (Holley 4150 series) is allowed. ARCA has been doing one thing that keeps the high dollar Cup motors at bay: they use a spec Mallory ignition box that limits the revs to a maximum of 8,800 rpm. The boxes are handed out at inspection and collected after the race to ensure uniform enforcement.

Nick Ramey of Roush Yates Racing Engines says RYR builds its ARCA engines very close to NASCAR versions – and that means VERY close. Because the NASCAR engines, which are of the flat tappet variety, get all the R&D time. But RYR doesn’t take advantage of ARCA’s allowance of roller cams. So Roush Yates ARCA motors are also flat tappet motors.

Ramey says the RYR builders advance the cam and cam timing and that allows them to “tune” the ARCA motor with things like header combos and a different intake manifold.

While the bulk of RYR Engines’ business rides on its extensive Cup motor work and development in areas like oil pan technology, valve springs and those flat tappet cams, the customer is the beneficiary. Though they still have to live with the 8,800 rpm rev limiter they manage to work around it for a lot less than the usual $50,000 it takes to buy a Cup motor.

The American Speed Association (ASA) has a long history with short track, pavement Late Models. While it has undergone some changes, it still services that market, running on short tracks only and with cars that are often readily available from local tracks. Their Super Late Models use template ABC Bodies, offset chassis and V8 engines with 500 cfm, 2-bbl carbs (Holley 4412).

Specifically, the breakdown works like this: There are 2,750 lbs cars with B&B, Mcgunegill, Schwanke, Ford S374D, Tesar, Hamner or Wegner sealed engines. They also run 2,800 lbs. cars that use 9:1 aluminum engines with the same 4412 Holley carburetor. ASA keeps a target of 500 horsepower for their cars and equalizes any differences with car weight.

Right now, the engines in ASA cars are evolving from 9:1 compression to the newer ACE 10.5:1. ACE stands for Aluminum Concept Engines – basically, engines with spec Brodix aluminum heads. There is no excessive porting allowed in the combustion chamber or inside the ports of these heads.

According to Bruce Mueller of B&B Racing Engines, the ACE engines account for the bulk of the motors. “Probably 65-70% of the engines used in ASA racing are 10.5:1,”?Mueller says. “The rest are the 9:1 engines, which are being rebuilt less these days.”

Mueller says B&B engines typically are used in about one third of the field, citing the economy as the main reason and the fact that racers tend to want the latest stuff and are usually willing to invest in it. “If you’re looking for what brands sell in ASA, it’s the Fords,”?he says.

Mueller gains repeat business by his service. “We take care of the customers,” he says “If something breaks, we fix it. Our engine lease programs are very popular and we keep them racing.”

The International Motor Contest Association (IMCA) was organized in 1915 and is the oldest active automobile racing sanctioning body in the United States. IMCA?is best known for its innovative modified rules that created hundreds of very competitive dirt and pavement race cars.

IMCA’s primary focus is weekly dirt track racing and this year will sanction events in 26 states, with 7,500 racers. IMCA sanction eight divisions of race cars, with engine rules specific to each division.?Cast iron cylinder heads and blocks are mandated except in the Sprint and Late Model divisions, which allow aluminum heads. The sanctioning body bans aluminum blocks and any titanium components except in the OEM Sport Compact (4 cylinder) division.

IMCA has some very restricted engine rules in their entry level divisions and allow more open engine rules in other divisions. Many of the IMCA divisions do not even allow porting or polishing, and flat-tappet cams and lifters are mandated in many divisions.

IMCA divisions incorporating “stock” type engine rules, such as with Hobby Stocks and SportMods, have power ranges around 350 hp. A typical Late Model or Modified engine produces 600 hp, while IMCA Stock Cars push 450 hp. IMCA’s goal, it says, is to maintain reasonable engine costs in each division, which can be obtained in a variety of ways with its rules. The sanctioning body also incorporates rpm limiters in most of its divisions to control costs and maintain competitive events.

In the late 1970s, when IMCA started its Modified class, it used an engine claimer rule that allowed a competitor to claim another’s engine. The intent was to keep costs down as the reasoning went that competitors wouldn’t pay to put big money in an engine that could be claimed for a set price. Anyone who was not willing to sell their engine was not allowed to race. Whether this rule had the desired effect is open to speculation.

The International Sport Compact Auto Racing Series (ISCARS) can be described as the rebirth of the former NASCAR Goody’s DASH Series for smaller cars without V8 engines. Today, the ASA-sanctioned series is known as America’s Premier Stock Car Tuner Series.

The cars have a tubular chassis with a 100? wheelbase and weigh 2,800 pounds including the driver. They use 15? x 10? or 15? x 8? tires and include bodies such as the Ford Focus and Mustang, Chevrolet Cruz and Honda Accord with room for additional manufacturers that fit the sport compact category.

For engines, ISCARS allows V6 (naturally aspirated) and four cylinder engines. With the fours, they allow all types of fuel injection but encourage direct port. They’ve also approved the use of computer control and boost systems. The limitation? A maximum output of 400 hp at the wheels. In this series, they incorporate a horsepower to weight rule. If a chassis dyno records over 400 hp, there is a weight penalty and vice versa.

ISCARS also encourages the use of “greener” fuels such as E85. Inside these engines, machining is limited to standard bore and stroke plus .010?. Head work on the ports and valves is also allowed.

Stock cars don’t always just turn left. The V8 StockCar Road Racing Series races on road courses using stock cars and, new for this year, includes Crane Cams as its title sponsor.

This road racing class is a touring, points championship series for high horsepower stock cars and GT machines. The series debuted in 2004 at Virginia International Raceway and 2012 marks the ninth year for the series. The V8 series has four classes of cars that compete on some of the most challenging road courses in the country including Sebring, Palm Beach, Carolina Motorsports Park, Daytona, Charlotte Motor Speedway, Homestead-Miami, Roebling Road and Road Atlanta.

The cars in competition are grouped into one of four categories. V8GT-1 are the sophisticated SCCA GT-1 and similar cars that make up to 800 horsepower and can hit 200 mph at tracks such as Daytona. V8GT-2 consists of mostly racers built from production cars such as Corvettes, Vipers, Panoz, BMW, Porsche, plus the tube frame SCCA GT2 cars.

The V8SPO class consists of ex-Cup, ARCA, USAR and Nationwide cars, plus the super late models often seen on short tracks around the country. Finally, the V8GTA class is made up of SCCA GTA-types and late model 500 hp tube frame stock cars weighing about 2,800 pounds with driver.

With V8 in their name, one would hope the series’ engine rules are very precise. They are and, more than that, the sanctioning body officially trumpet their objective to “assemble” an engine rather than “develop” one – a serious attempt to keep costs down. As a result, modifications to the mostly original equipment parts they allow are pretty limited.

For a traditional engine, the target power range is 525 hp. For an upgraded LS1 engine, it’s 475 hp. A base LS1, ZZ-4, and 604 are targeted at 440 hp while a restricted engine shoots for 500 hp. They are working on a (restricted) LS3 based option that will be equivalent to the upgraded LS.

The class breakdowns include the ex-NASCAR cars using SB2.2 Chevy, Ford C3 and D3 and Dodge motors. All can go up to 366 cid at 2,780 pounds with driver. Specifics include roller cams, around 12:1 compression, dry sump and a single Holley 4150 carb.

The core rules are similar to many racing circuits. All engines are normally aspirated, pushrod V8s. SBC 18 degree, 23 degree, LS Series, and current conventional SLM GM, Fords and Dodges allowed. Aftermarket cast iron engine blocks are allowed, but must be equal to or greater in weight and exterior dimensions compared to the original manufacturer of the same make and model.

The only aluminum small block allowed is the LS1 utilizing the stock fuel injection unit. Crankshafts must be made of steel or iron. The stroke may be increased or decreased. Minimal allowable weight is 38 pounds. Lightweight, knife-edge, 180-degree, pendulum cut, scalloped, and/or undercut counterweight crankshafts are allowed.

Connecting rods must be solid steel. No titanium, aluminum, stainless steel or composite rods are allowed. Water pumps must be OEM type and impellers may be altered for improved cooling. The top motors are in the 800-850 hp area and are twisted in the 9,000 rpm range.

So the many types of stock cars racing today have just as many types of engines in them – maybe more.

UNOH High Performance Motorsports

The opening page of the University of Northwestern Ohio’s High Performance Motorsports department says it all. “The level of professionalism required by race teams, performance machine shops, and sanctioning bodies such as NASCAR and ARCA, is at an all-time high. The UNOH College of Applied Technologies’ High Performance Department’s reputation for producing highly-educated graduates means your diploma or associate degree will give you a distinct advantage in a competitive workplace.”

They invented the high performance/ motorsports program in 1992. And in 2006, they took motorsports education to a new level with the largest facility in the country dedicated to learning the science of high performance vehicles – a seven acre, 70,000 square foot high performance motorsports complex. Inside you’ll find cutting-edge technology and equipment. Currently, there are a total of 2,400 students at the University of Northwestern Ohio that are enrolled in the College of Applied Technologies. There are several programs in the College of Applied Technologies.

All of their Automotive, Diesel, Agricultural, Alternate Fuels, Agricultural and of course, High Performance Motorsports programs have engine classes in them that focus on diagnosis as well as tear down and assembly. Any student involved in the College of Applied Technology program will be exposed to engine classes. Students enrolled in the High Performance program need to take some prerequisite classes in one or the other programs so that they are assured to have the basic knowledge before transitioning into the High Performance program. For these, they have the following:

Engine Machining – Students learn and become proficient from the machines that are representative of equipment in an automotive machine shop. Align hone, cylinder boring, cylinder honing, block and head resurfacing, seat and guide repairs as well as installing replacement seat and guides, performing valve seat angles with carbide cutters on seat and guide machines.

Fuel Systems and Testing – This class is where students will become proficient in engine tuning techniques utilizing engine and chassis dynos.

Custom Engine Building – In this class, each component is evaluated on what should be used depending on the application the engine is being built for and students typically will work on either their own projects or a project engine of the University.

All classes in the college of Technology are six week sessions and depending on the class, the percentage of hands-on shop work and classroom lecture on theory will differ.