Engine builds always seem to come at a price versus power compromise. What if you could build a high performance engine at half the cost of an off-the-shelf racing engine from the big dollar engine builders? That was our goal with the Smart Money Engine Build (SMEB). We wanted a true performer with top shelf parts that would make great power and last for a couple of seasons. This is a real world 355 c.i. small block Chevy build and we bring you all the details, the triumphs and the tragedies, as we put together our Sport Mod engine on a budget. This is our story.
Planning started on this engine build over the Christmas break in 2009. Our crew had just returned from the Professional Racing Industry (PRI) trade show in Orlando, Florida, where we had talked with representatives from every company that makes components for dirt track cars. “Representatives” is not really a good word to use here; “specialists” is more like it. The folks that we talked to are the guys and gals that have years designing and building these parts. They know and understand how the parts work and how they work in relationship with other parts in the engines. Needless to say, we paid attention and took lots of notes.
We priced similar completed engines on the open market and came up with a mean average cost of $17,000 dollars for the performance that we wanted. Our overall goal was to come in at half the cost of one of these engines, so that gave us a target dollar amount “not to exceed”. Top shelf parts in a complete engine with high performance for under 8,500 U S dollars? We had our target, now the challenge was to identify all the components we would need to make that goal a reality.
Engine Block and Sport Mod Rules
Almost all Sport Mod rules state that you have to run a cast iron block and heads. Unless you are in a sport mod class that requires factory equipment, our build sheet will work just fine. The important thing is to build to your rules. Our local rules allowed for aftermarket block and heads.
While there are some great cast iron blocks on the market, like DART Machinery’s SHP line, we were already sweating the $8,500 dollar brick wall on our build, so we reclaimed a used stock SBC 350 with four bolt mains from the junkyard. The price on our block was $250 and with another $750 for cleaning and machining, we hit the cash register at a grand. That bought us a completely reworked block, zero decked with a half fill of grout in the water jacket to stiffen the bores and dampen harmonics. The mains were line honed, lifter bores were checked and honed and the cylinders were bored out to 0.030” over stock. Honestly, buying a good quality block from an aftermarket source would have fit well into this budget. Check your local track rules and if you are allowed to run an aftermarket block, it’s probably a better idea. After all, The engine block is the foundation for the engine.
There is one simple rule regarding rotating assembly parts for race engines: Buy the best parts that you can afford. Race engines run at higher rpm speeds and most sportsman racers require an engine to run a full season without a rebuild. This necessitates buying better parts when you assemble the engine. Scat Enterprises, Inc. is known for making high quality performance automotive parts at reasonable prices. Scat crankshafts are one of our favorites and have been featured in several of our other project builds, so it was an easy choice to go with Scat on the rotating assembly components.
Here’s what you may not know about Scat Enterprises; Founder Tom Leib has designed engine parts that have been in Victory Lane at Daytona, Indianapolis, Baja, and every NHRA track that exists. Leib has also designed sprint car engines for cars driven by Tony Stewart and Jeff Gordon. If his components were good enough for Stewart and Gordon, they are certainly good enough for our crew. Leib told us that he has his crankshafts “manufactured offshore” but they undergo a “very stringent quality assurance inspection before they are shipped back” for resale to the engine builders. According to Leib, “making sure the manufacturing plant is keeping up with our specifications is key to getting the best product.” We were very familiar with SCAT’s crankshafts from previous engine builds, so our confidence level was extremely high.
Scat’s Ultra-Light Crankshaft
We selected the Scat Super-light 350 Chevy Forged Crankshaft (Part #4-350-3500-5700-3) with a price tag around a grand. We knew that the engine would be spinning over 6,500 regularly, so a cast piece probably wouldn’t hold up. Scat’s forged crankshafts are designed with a “symmetrical counterweight system” that basically moves a lot of the weight to the center of the crankshaft. It doesn’t take a lot of brainpower to understand that weight in the center of a dynamic component provides greater stability and less flexing. There are several pluses to using this crankshaft; the lighter weight means that there is less energy spent moving the rotating weight and there is less stress on the crankshaft itself, which means greater durability.
Rotating components under load experience some deformation of the part. When the load is removed, the part returns back to it’s original shape. This constant loading and unloading happens continuously when the engine is running. The ability of a component to withstand this continuous loading is dependent on the material’s elasticity (modulus of elasticity) and the dynamic weight of the part. SCAT’s symmetrical counterweight design is manufactured to lower the resistance offered during acceleration and deceleration. Less mass = less resistance. For our money, the scat crankshaft was light enough and strong enough to make a big difference power wise. Price: At $1,250, it’s not the cheapest crankshaft on the market but it’s features far outweigh the expense.
- 2-piece Rear Main Seal
- 3.500” Stroke
- Forged 4340 Steel
- Internal Balanced
- Cross Drilled Mains
- 2.100 Rod Journal Pin
- Standard Crankshaft Style Snout
Scat Q-Light Connecting Rods
Keeping in mind that this is a premium engine build project, premium in quality parts and performance, so we excluded anything but an H-beam Steel connecting rod. This is not the place to skimp. More connecting rods break than pistons or crankshafts. We chose to stay with Scat Enterprises for our connecting rods by picking the Scat Q-Light 350 Chevy H-Beam Rod set (Part #2-350-5700-2100-QL).
These rods are hearty enough for nitrous or supercharged applications with the added bonus of weighing in at a svelte 550 grams per copy. Balanced at the factory within 1 gram, these connecting rods are the real deal for a pony express engine that will be driven hard all night. We had our engine builder check the weights on these rods and just as advertised, all were within 1 gram of each other. We like a company that keeps true to their advertising, so this also increased our respect for SCAT Enterprises, as well as our confidence in the engine build. The key to these rods is putting the mass in the right place. These rods support a pretty beefy .927″ wrist pin which helps in eliminating the common wrist pin bending problems in a high rpm engine. Price tag for the connecting rods: about $500, and well worth it.
We needed some real help in figuring out the best piston to use with our combination of Vortec Heads, Scat rotating Assembly and shorty type headers that are common in modified racing, so we called Stacey Stone, the circle track expert at JE Pistons. Stone understood our project engine build and guided us to an off the shelf piston made in the JE facility under the SRP brand name.
SRP’s Dome top pistons (Part #206040) for small block Chevy 350 engines fill the bill quite nicely. The solid dome design and forged aluminum contribute strength to the robustly solid piston, enough that we wouldn’t have to worry about piston problems for the life of the engine. The pistons have provisions for press fit or floating pin installation. Our connecting rods were floating pin design which made our engine builder happy. The wrist pin grooves are moved in toward the center of the piston and are supported with more material where the wrist pins are located. That allows for a total weight reduction of the piston without sacrificing strength.
These SRP pistons are forged from 2618 aluminum alloy, a material that is popular in aircraft engines. The piston domes are CNC machined with radiused valve reliefs that are designed to optimize flame travel. Priced right around $500 for a set of eight, they come with pin fittings, spiro locks and wrist pins.
One of the key areas in selecting SRP pistons for this project build lay within the ring set. Using the lower friction 1/16”, 1/16”, 3/16” rings. The top ring is Bar D style ductile iron with a PlasMoly coating that reduces the friction even more. The second ring is a taper D-Wall style iron ring with phosphate coating. Phosphate coatings are used on steel parts for corrosion resistance andlubricity. Lastly, the oil ring set has standard tension carbon steel oil rails chrome coated. Together, these rings comprise a very strong but low friction ring set that will help produce power without creating excessive drag. The ring set runs about $140 for a complete set. With the SRP pistons and rings, you get what you expect plus a little more. Total for pistons and rings: $640.
For this engine build there was only one name in engine bearings, Clevite. Especially in a circle track engine. Clevite and dirt track racing have been joined since NASCAR started in 1948 and every event was run on a dirt track. If you are building any serious dirt track engine, from dirt late models and sprint cars to open wheel modifieds, Clevite is the only choice.
We worked with Bill McKnight, bearing guru at Mahle-Clevite Inc., to find the perfect bearing for our higher RPM short track motor. McKnight directed us to the H-Series connecting rod bearings (Part #CB663HN) which is designed as a high performance bearing that is narrow for crankshafts with oversize fillets. These bearings run comfortably in the mid to high RPM range and are manufactured without flash coating for quicker and better seating. Because they are not flash coated, these bearings are often called “the ugly bearings.” Price tag on a set of these will run you about $130.
With McKnight’s help, we also picked the H-Series main bearings (Part #MS909H) primarily for the same properties as our connecting rod bearings. These are designed to run mid to higher RPMs and are chamfered on the sides for crankshaft fillet clearance. They are available with oil grooves in both bearing halves or grooves only on one bearing half. We picked the 180 degree oil groove bearings for more of a hydroplaning effect on the smooth side of the bearing. A set of these bearings is about $65 at your favorite parts store.
We opted to stay with our primary circle track bearing manufacturer when it came to camshaft bearings. The SH1349S Clevite camshaft bearing set is a steel backed, copper-lead center layer with a soft lead alloy outer layer bearing set. Designed to withstand friction, dirt, misalignment, corrosion and heat, these bearings are a direct replacement fit for OEM bearings with longer bearing and journal life. At $25 per set, these are a deal. Total bearing cost: $220
Milodon Oil Pump
Milodon’s high volume oil pump (Part #18750) was our choice for lubrication supply throughout the engine. Advertised to supply a 25% increase in volume at 65-70 pounds of max hot oil pressure, this pump is 3/8” deeper than a stock pump and utilizes a 5/8” inlet tube. Modestly priced at $42, this oil pump has a stronger neck area where it bolts to the block and is stronger at the bolt pad area than stock pumps. Stock oil pumps tend to brake at the mounting neck under dirt track conditions where hard collisions and rutted tracks cause a lot of vibration to these components. The added material in the oil pump neck area will keep the oil pump supplying oil to your engine when you need it most.
For our gaskets & sealing needs, we chose another legendary name in circle track racing, Mr Gasket. Since 1965, when company founder Joe Hrudka started operating as Mr. Gasket, the company has become a staple for do-it-yourself racers. Using the logic of “why would you buy engine gaskets from a company that was known for products other than gaskets?”, we naturally migrated to the company that specializes in engine gaskets to the extent that they named the company after gaskets. We opted for several items from the Mr. Gasket catalog for our top quality engine build.
We chose brass freeze plugs (Part #6481) for the corrosion resistance. The OEM freeze plugs are ferrous metal (steel) which contribute to the corrosion process where brass is a non-ferrous metal and more resistant to the electrochemical oxidation that takes place in corrosion. The Screw-in rocker studs (Part #1074) are a heat treated, grade 8 alloy steel for stregth. The base of the studs have an enlarged radius for even more strength which provides a stable support for the rocker arms. In our mind, not even superman could pull these studs out without a wrench.
Mr Gaskets SBC overhaul gasket kit (Part #5991) includes all the gaskets required for a complete rebuild. This set is designed fro high performance street vehicles, drag race engines and oval track engines. While it comes with head gaskets, we opted to go with another head gasket from Mr. Gasket for our higher compression engine.
We initially chose the SBC heavy duty head gasket (Part #5799G) but quickly decided to go with Mr. Gaskets multi-layered gasket (Part #3144G) for the increased compression application. We had our engine builder mic out the tolerances that we needed to get our compression ratio up to 12:1, then selected the proper dimension gasket to go with engine build. For engines that are going to be run hard, MLS gaskets are worth the investment. These head gaskets are designed to withstand supercharged, turbocharged, nitrous oxide and extreme compression ratios. If you don’t want to take any chances with head gaskets, this is the way to go.
We finished up our Mr. Gasket shopping list with the Camshaft bolt lock plate (Part #948G) and Chevy 350 exhaust gasket (Part #5965). The camshaft bolt lock plate is a must have item to ensure that the bolts holding the timing chain sprocket to the camshaft don’t vibrate loose under the high frequency vibrations caused by the valvetrain harmonics. The exhaust gasket is a direct fit for the Bowtie Vortec heads where the larger ports make a difference. The grand total for our gaskets was $260
Hamburger Oil Pan
We selected another historic company for our oil pan, Hamburger’s Performance Products. Hamburger oil pans started in 1978 and rapidly became one of the “must have” products for circle track racers. They were so good that Dale Earnhardt Sr. was a frequent customer. We picked Hamburger’s oval track and road race oil pan (Part #3047) that features a 7 quart capacity with trap door baffles to keep the oil pump pickup submerged at all times. Other features include a magnetic drain plug, expanded metal directional windage screen and crankshaft oil scraper for oil control. These pans are designed to accept a stock GM starter, so a racing starter will fit with no problem. These pans are a bargain at 286 bucks when you consider the durability and functionality that they add to the engine’s performance.
Cylinder heads were a real “no brainer.” The comparison between Gen I Chevy heads and Vortec heads has proven that whenever the rules allow, Vortec heads are by far are the way to go. The Bowtie heads have long been a favorite of the modified crowd, so we investigated the Bowtie Vortecs. Our car would be running under rules that specified a Holley 4412 carburetor, so we called John Dickey at AED Performance Fuel System Components. AED has a good handle on how the engine responds with different components, so we considered John Dickey a trusted resource of information in picking the right components for our build. Dickey told us that the “Large port Bowtie heads were probably too much for a two barrel carb setup,” so we opted for the small port Bowtie Vortec heads.
The good news is that the Bowtie heads can be purchased completely assembled and ready to bolt on or bare. These heads feature 185cc intake ports and 65cc exhaust ports, machined for 2” intake valves and 1.55” exhaust valves. The price tag on a complete set of assembled, ready to install, Bowtie Vortec heads (Part #25534421) is around $1,050. We were looking to squeeze every ounce of HP out of our dynamo so we chose the bare heads (Part #25534351) at $700 for the pair.
We stayed with the GM Performance Parts (GMPP) 2.00″ solid stem intake valves (Part #12363757) and 1.55″ solid exhaust valves (Part #12363758) These high performance intake valves are constructed from stainless steel for improved strength and corrosion resistance. With undercut stems to improve flow and reduce weight and featuring 11/32” chrome-plated stems to reduce wear and galling with hardened tips to withstand high loads. Cost against the budget: $320
Edelbrock Super Victor Manifold
To finish off our engine assembly to the point where most engine builders sell the unit as a complete engine, we needed to add an intake manifold. For our heads we needed to get the Edelbrock Super Victor Manifold (Part #2814) that is specifically designed for GM cast iron Vortec Bowtie heads. The raised runners on this manifold match the port shape and location of these heads. The bonus in this manifold is that the orignal GM 6 bolt pattern is used on the intake that allows taking advantage of the bowtie heads dual bolt pattern for a tight seal.
The Super Victor Manifold also incorporates 7/8 inch of additional carb pad height. Going with an Edelbrock manifold was a given, after all, is there a dirt track engine anywhere that is not using an Edelbrock manifold? This is the only option for the Bowtie Vortec heads without having serious machine work done to the heads. Why bother risking damage to the heads by having your machinist match the bores when Edelbrock has already done the work and produced an intake manifold that matches perfectly and flows better for these heads? Price tag: $290, which is cheaper than the labor to have your machinist drill new mounting holes.
Hamburger Carb Spacer
Hamburger’s Performance Products carb spacer (Part #3223) was another “must have” for this build. Adapting a 2 barrel carburetor to our Edelbrock Super Victor intake required an adapter spacer, and we wanted one that was adjustable on the intake and had individual venturi ports. The Hamburger carb spacer fit the bill perfectly by adding 1 inch of spacing for better flow while keeping the fuel atomization maximized. This allows the engine to draw the air/fuel mixture to where the greatest demand is. Inexpensive performance at around $112. Milled from 6061 T6 grade aluminum billet, they are guaranteed for life. These spacers are flow tested to provide the best potential for making serious horsepower, plus you can optimize the flow characteristics by sliding the spacer forward or back on the manifold. Better flow means more horsepower, and this spacer allows you to dial in the best flow for your individual engine characteristics.
AED Eliminator Carb
Unwilling to slap on any old 4412 Holley Carb, especially after we handpicked every component in the engine to make extreme power, we sought out John Dickey of AED Performance Fuel System Components. John is one of those guys that takes all the information that you can provide him, including the combination of parts, the track dimensions, altitude, and your date of birth, to come up with a carb that flows perfectly for your application.
True, most Sport Mod rules require a Holley 4412 carb, that fits the tech gauges. But not all 4412 carbs are created equal. The AED Eliminator has undergone several tests that show a substantial improvement in torque and horsepower over a broader rpm band. The carburetor is fully blueprinted to match the combination of components that each customer is using. John hooked us up with AED’s 500 Eliminator Carb. Designed for classes that require stock venturi, baseplate and boosters, Dickey’s crew has redesigned the fuel circuitry in the metering block to achieve a consistent fuel curve throughout the entire rpm range. This is critical in broadening the usable power band expecially in a limited induction engine.
For the productivity that it delivers, the price per horsepower ratio is much better than many other “performance enhancing” parts. We asked Dickey how they redesigned the fuel circuitry and he explained; “hundreds of hours went into flow bench testing and hundreds of more hours went into track testing.” Dickey was not willing to give away these company secrets and thousands of hours of research and development to their competitors who will undoubtably be reading this build article. What Dickey would tell us is; “It’s about RPM. Camshaft & the intake port of the cylinder head play a key role in the rpm range.” AED designs each carb around these other pieces of the puzzle to make them work as a precision airflow team.
The performance is so good, these carbs are used in NASCAR sanctioned Limited Late Model classes. While it may sound like this is a budget killer component, AED’s 500 Eliminator is priced at a reasonable 640 bucks, and we felt that we couldn’t afford not to have one in a premium engine build.
To outfit the Bowtie heads with valvetrain that would withstand the punishment that we intended to subject the engine to, we selected a well respected manufacturer that has a solid record in making hardcore racing parts, Lunati. We talked with Derek Scott and Jeff Sams at Lunati about the combination of parts that we already had, and what our local track rules were. Scott and Sams were interested in helping us get the most out of our beast so they asked a few more questions about track size, and max rpms. Based on the 3/8 mile track and a 7,500 rpm range, our Lunati technical advisors suggested Lunati’s dual spring kit (Part #73100K2LUN) which includes valve springs, retainers and keepers. Priced at $180 for the kit, these valve springs can handle valve lift up to 0.660” which is way more than what we would need. The retainers and keepers are CNC manufactured out of 4140 alloy steel. Overall tough pieces that met our demanding needs.
While we were shopping at Lunati, Derek Scott sold us on a Custom Lunati Nitrided Camshaft (Part #40199), Lunati solid lifters (Part #70984LUN) and the Lunati timing set (Part #93113). Sams told us that the “Lunati mechanical, solid lifters are designed to meter the exact amount of oil while maintaining the precise lash needed to allow the camshaft to perform at its best.” These feature a center oiling hole on the face of the lifter to lubricate the camshaft lobe surface. For high lift mechanical lifter camshafts, these oiling holes would help the cam survive the break-in period.
The Lunati timing set is a full roller timing set complete with a torrington bearing for the thrust surface that minimizes wear. The crankshaft gear has three keyways for accurate setting of timing. The keyways allow for zero timing or adding or removing 4 degrees of timing. Our custom Lunati cam followed Lunati cam grind TF71/TF74 S107.
We capped off our valve train with COMP Cams Ultra Pro Magnum roller rocker arms (Part #1605-16) constructed out of 8650 chromemoly steel with a web-like design that delivers increased strength & rigidity. We chose the 1.6 ratio rocker arms to take advantage of their increased air flow properties. At $340 bucks, these are a lifetime investment.
- Lobe separation 107 degrees +4 degrees advanced
- Advertised Duration: 283 intake/ 287 exhaust
- Duration at .050”: 255 intake / 259 exhaust
- Gross valve lift with 1.5 ratio rocker: .550” intake/ .560” exhaust
- 1.6 ratio rocker: .587” intake/ .598” exhaust
- Lunati Solid Lifters $180
- Lunati Custom Cam $200
- Lunati Timing Set $60
- Lunati Valve Springs $180
- COMP Cams rockers: $340
- Valvetrain Total: $960
- GMPP Intake Valves $160
- GMPP Exhaust Valves $160
Flexplate and Harmonic Dampner
Staying with the dynamic rotating component specialists at Scat Enterprises, we selected their 153- tooth Flexplate (Part # FP305) and SBC Dampner (Part #D-8000). The flexplate is neutral balanced and will work with just about any internally balanced SBC engines with 2 piece rear main seals. .035” thicker than the stock flexplate and it incorporates a dual converter bolt pattern, with double welded ring gears and SFI 29.1 approved, priced around $55. The D-8000 PowerForce Dampner from Scat is a 6 3/4″ balancer for internal balanced engines running higher RPMs than stock. Elastomer bonded to prevent outer ring slippage with removable counterweights and precision machined to tight tolerances, this dampner has easy to read timing marks which help in timing accuracy. A quality and affordable high performance part that only hit our budget at $52. It made sense to us that SCAT Enterprises was a distributor of the PowerForce Dampner. Leib’s company likes to ensure that specifications and tolerances are controlled at the factory and PowerForce has a great reputation for keeping tight tolerances in their products.
Hamburger Circle Track Valve Covers
We picked Hamburger Performance Products valve covers (Part #1069) at $199 for the set to cover our valvetrain. These are made specifically for circle track engines that have Vortec heads. Cast aluminum with two breather holes on the driver’s side valve cover, these are polished to a mirror like finish and look great on the engine. In addition to being lightweight aluminum, these valve covers feature a center bolt design and the breather tubes are double baffled to prevent “blow by.” Our favorite feature in these valve covers is the counter-sunk mounting bolts. These result in a smooth surface across the top of the covers and hold the valve covers tight to the heads. There is very little chance that they will leak regardless of what gasket you use. The clamping power of the machined center mount bolts is a significant improvement over the original equipment.
Capping off our project engine build is a nice set of Schoenfeld Headers. Our chassis is fairly narrow in the engine bay, and the only headers that fit without problem are the IMCA shorty style headers. Schoenfeld Headers has become the “go to” people for dirt modified headers, especially the shorty style headers. We talked with Mark Brailey at Schoenfeld, and explained our combination to him. We also explained why we were looking for a shorty style header and what recommendation he had. Based on the dyno number from Schoenfeld’s in-house dyno, Brailey directed us to their IMCA Short Header that features shorter primaries for a crisp throttle response. Priced close to $300, these shorty headers are compact enough to fit in even the tightest of engine compartments and still deliver all the power that Schoenfeld Headers have become known for.
Even with our additional add-ons that you would not get with an engine purchased from a high performance engine builder, we ended up with the grand total of $7826.00. If you were to pay a machine shop to assemble the engine, we estimate the labor cost to be $2,000 to $2,500 which still keeps the budget under 10 grand and still have the high quality parts that exceed most machine shop’s offerings. We plan on installing this project engine in our Sport Modified project car and getting it out on the track before the end of the Southern California racing season and we will be updating you on the status of this build and how it performs on the track. Initially, we believe that we have completed our project engine and hit the goals that we outlined in the beginning. We have a high performance engine with top quality parts that exceed engines built by top engine builders, and we have achieved that at half the cost. Now we need to get the engine out on the track and prove the operational end of this build. Stay tuned for the track testing updates on this engine build.