Flogged for the Fairgrounds

In the beginning, we intended to build a lumpy-sounding big-block that would rumble the pavement while it cruised the fairgrounds of the Western United States. What we ended up with was one shag nasty mega motor that not only shakes the earth, but also produces some mighty impressive horsepower numbers as well. In doing so, we made careful parts selections, like with all build-ups. To further the cause, we called in the folks at Speed-O-Motive to help coordinate and assemble this new 540-inch monster. Keeping its intended purpose (and supercharger) in mind, we arrived at 8:1 compression. Everything went according to plan, as the Speed-O guys quickly showed us their capabilities. This shop builds lots of engines, powering everything from restorations to racing and marine applications.

Once the parts pile was complete, things progressed at a rapid rate, thanks to Speed-O-Motive's state-of-the-art machining department. And through the build-up, we only experienced one bummer--the brand-new DTS dyno was still being plumbed and wired, so we had to quantify the numbers out at the Vrbancic Brothers shop, located about 30 miles east of Speed-O-Motive. No big. Check it out, as we go through the build-up sequence and you're sure to see why this monster shakes the pavement.

Though everybody might have...        read full caption Though everybody might have his own preferred method, proper cylinder wall cleaning is paramount to a successful engine build. Charlie Presby, our assembly pro, relies on lacquer thinner for this final clean-up chore, which is available at most any hardware store. Notice the lifter valley area, painted with Glyptol, for more efficient oil return.	Dart supplies its own special...        read full caption Dart supplies its own special cam bearings, which feature improved oiling characteristics, as opposed to "off-the-shelf bearings." Once a generous amount of the slippery stuff was applied to the bearings, our Lunati (PN 50256) cam was installed. The specs are: .804-inch lift (intake), .755-inch (exhaust) with a 1.7:1-ratio rocker arm. The duration numbers are aggressive, with 285 degrees duration (at .050-inch tappet lift), and 295 degrees (also at .050) on the exhaust side. Lobe separation is 114 degrees and total advertised duration is a rumpity 326 (intake) and 338 (exhaust).	We're using a Scat 4340 stroker...        read full caption We're using a Scat 4340 stroker crank (PN 4-454-4250-63), similar to those used in motors producing over 1,200 hp. This crank features mirror-polished journals, smooth counter-weight edges (for minimum drag), and large chamfered oiling holes. The Scat journals ride on Federal-Mogul main bearings (PN 141M).
Charlie torqued the ductile...        read full caption Charlie torqued the ductile iron rear main bearing cap to 105 ft-lb before checking the crankshaft end-play (.002--.006-inch is recommended).	Mounting pistons to the Scat...        read full caption Mounting pistons to the Scat 4340 H-Beam rods (PN 245463852200) can be an exercise in futility, if you've never messed with Spiro-Locs. These spring-steel babies are difficult to work with, but do provide a positive way to lock the pistons to the pins. As shown in the photo, Spiro-Locs have to be spread apart and worked into a receiver groove, bit by bit. Charlie used Clevite assembly lube (or "red grease") on the pins, to help ensure that the floater pin doesn't seize. Note: Installing them is much easier than removing them!	After checking the JE Plasma...        read full caption After checking the JE Plasma Moly "file-to-fit" rings (PN J100F8-4500-5) in each bore, ring end gap was set to .027-inches, and filed one by one. Speed-O-Motive uses this cool tool, which combines an electric motor, grinding wheel, ring vise, and dial indicator all in one handy unit.
Just like Spiro-Locs, piston...        read full caption Just like Spiro-Locs, piston rings can be stubborn, too. Once they're all in place, Charlie's preferred method of ring positioning is: top ring facing top of block--second ring facing down--oil ring separated 90-degrees (right and left). When we asked what the most important benefits of proper ring positioning were, he said, "Ring placement is critical, because proper alignment will help keep heat off the piston itself, and away from the top ring."	Clevite H-Series rod bearings...        read full caption Clevite H-Series rod bearings (PN 8-7200CH) were used. Again, when we asked Charlie about the benefits, he said, "They offer a harder, more durable composition, which helps them handle the internal pressures of a blower motor."	Prior to sliding the pistons...        read full caption Prior to sliding the pistons in the bores, each ring pack is oiled liberally before placing them in the ring compressor.
You'll find that a tapered...        read full caption You'll find that a tapered ring compressor is much easier to use, as opposed to the hand-held "pliers-type." However, still use caution so as not to change your ring positioning, while properly aligning the piston and rod in the bore.	With one rod and piston in...        read full caption With one rod and piston in place, Charlie torqued the cap to 62 ft-lb, as recommended by Scat, to assure proper bearing seating.	Next, the piston is checked...        read full caption Next, the piston is checked at TDC. This combination is designed to run with "zero deck," meaning the piston top is level with the deck of the block.
Here's an important step that...        read full caption Here's an important step that at-home engine builders should never skip. Degreeing the camshaft verifies that it's phased correctly with the crankshaft.	Before installing the ARP...        read full caption Before installing the ARP screw-in head studs, the threads were coated with moly assembly lube, to avoid galling.	This shot was taken just after...        read full caption This shot was taken just after installing the Milodon high-volume oil pump (PN 18760) and windage tray. The windage tray helps re-direct oil thrown off the rotating assembly and prevents the crankshaft from spinning in oil, which robs horsepower. Notice how gasket technology has progressed. That Fel-Pro one-piece oil pan gasket is a thing of beauty.
While getting ready to button...        read full caption While getting ready to button up the bottom end, Charlie set the Milodon deep-sump pan (PN 30950) in place. Clearance between the pump and the pan should be .250 to .500 inch.	Just like when your wife goes...        read full caption Just like when your wife goes to the mall, trial fitting everything helps ensure success. Here, Charlie is double-checking the receiver grooves machined into the cylinder heads that ensure optimum sealing of combustion chamber pressure. Our Fel Pro head gaskets feature steel-shim "fire rings" that actually lock into these grooves.	We chose Dart Pro 1 CNC aluminum...        read full caption We chose Dart Pro 1 CNC aluminum cylinder heads (PN 19300136), which feature a 345cc intake port and 119cc chamber volume. Intake and exhaust valves are 2.30 and 1.88 inches, respectively. Here, Charlie torques them to 65 ft-lb.
After completing the valvetrain...        read full caption After completing the valvetrain assembly, the lash was pre-set (.026 intake and .028 exhaust), as recommended by Lunati. Following its initial firing on the dyno, the lash was reset, once the motor was warm.	Dart recommends using its...        read full caption Dart recommends using its own stud girdle when using any cam over .625 lift. Stud girdles prevent stud deflection, increase the operating stability of the rockers and pushrods, help keep the valves adjusted under high rpm, and can also help prevent rocker failure in severe-duty applications. Please note: Dart stud girdles are specially designed to fit the valve angles of Dart cylinder heads.	Next, the Weiand blower manifold...        read full caption Next, the Weiand blower manifold was mounted, using our Fel Pro (PN 1239) intake set (and liberal beads of silicone on the end rails).
August Cederstrand (center),...        read full caption August Cederstrand (center), Speed-O-Motive's Shop Foreman, helps position the Weiand 8-71 blower (PN 7186P). The guys told us it's important to use the aluminum mounting studs provided, as they're intended to shear under any abnormal engine loads.	Next, came the Weiand adapter...        read full caption Next, came the Weiand adapter plate and two Holley 650cfm carbs, which are specially designed for twin-carb blower applications (PN 0-80573S). Power valves are plumbed into the intake manifold for boost reference on supercharged applications. Always use caution when bolting on a carburetor adapter plate, and tighten the fasteners evenly for proper sealing. Likewise, with the carb base plates.	Here's our finished engine...        read full caption Here's our finished engine before final bolt-ons like the MSD distributor and ignition wires, water pump, and pulleys. The guys at Speed-O-Motive made sure we had a set of custom-engraved sheetmetal valve covers to complete the project. They're available by mail order, over the counter, or as an option on any Speed-O-Motive complete engine.
As with most of our deadlines,...        read full caption As with most of our deadlines, we didn't have time to drill and install the breathers in our engraved valve covers, so we bolted on this set of ball-milled units for dyno flogging purposes. Bob Vrbancic, engine builder and tuner, prepared the engine for break-in, followed by a series of full-power pulls. The dyno chart reveals more than 11 pounds of boost, in excess of 1,000 hp (at 7,000 rpm on race gas).

During the prep and machining...        read full caption During the prep and machining process, Speed-O-Motive clearanced the bottom end for the Scat stroker crank, bored the cylinders (from 4.250 to 4.500 inches), and align-bored the Dart "Big M" block (PN 31273344).