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 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.Though everybody might have his own preferred method, proper cylinder wall cleaning is par 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).Dart supplies its own special cam bearings, which feature improved oiling characteristics, 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).We're using a Scat 4340 stroker crank (PN 4-454-4250-63), similar to those used in motors Charlie torqued the ductile iron rear main bearing cap to 105 ft-lb before checking the crankshaft end-play (.002--.006-inch is recommended).Charlie torqued the ductile iron rear main bearing cap to 105 ft-lb before checking the cr 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!Mounting pistons to the Scat 4340 H-Beam rods (PN 245463852200) can be an exercise in futi 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.After checking the JE Plasma Moly "file-to-fit" rings (PN J100F8-4500-5) in each bore, rin 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."Just like Spiro-Locs, piston rings can be stubborn, too. Once they're all in place, Charli 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."Clevite H-Series rod bearings (PN 8-7200CH) were used. Again, when we asked Charlie about Prior to sliding the pistons in the bores, each ring pack is oiled liberally before placing them in the ring compressor.Prior to sliding the pistons in the bores, each ring pack is oiled liberally before placin 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.You'll find that a tapered ring compressor is much easier to use, as opposed to the hand-h With one rod and piston in place, Charlie torqued the cap to 62 ft-lb, as recommended by Scat, to assure proper bearing seating.With one rod and piston in place, Charlie torqued the cap to 62 ft-lb, as recommended by S 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.Next, the piston is checked at TDC. This combination is designed to run with "zero deck," 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.Here's an important step that at-home engine builders should never skip. Degreeing the cam Before installing the ARP screw-in head studs, the threads were coated with moly assembly lube, to avoid galling.Before installing the ARP screw-in head studs, the threads were coated with moly assembly 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.This shot was taken just after installing the Milodon high-volume oil pump (PN 18760) and 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.While getting ready to button up the bottom end, Charlie set the Milodon deep-sump pan (PN 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.Just like when your wife goes to the mall, trial fitting everything helps ensure success. 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.We chose Dart Pro 1 CNC aluminum cylinder heads (PN 19300136), which feature a 345cc intak 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.After completing the valvetrain assembly, the lash was pre-set (.026 intake and .028 exhau 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.Dart recommends using its own stud girdle when using any cam over .625 lift. Stud girdles Next, the Weiand blower manifold was mounted, using our Fel Pro (PN 1239) intake set (and liberal beads of silicone on the end rails).Next, the Weiand blower manifold was mounted, using our Fel Pro (PN 1239) intake set (and 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.August Cederstrand (center), Speed-O-Motive's Shop Foreman, helps position the Weiand 8-71 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.Next, came the Weiand adapter plate and two Holley 650cfm carbs, which are specially desig 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.Here's our finished engine before final bolt-ons like the MSD distributor and ignition wir 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).As with most of our deadlines, we didn't have time to drill and install the breathers in o DYNO CHART Timing: 36° Jets: 74 pri. 84 sec. Fuel: Union 114 RPM LB-FT HP BOOST 4000 823 627 9.4 4100 829 647 9.4 4200 832 666 9.4 4300 838 686 9.4 4400 843 706 9.4 4500 843 723 9.4 4600 845 740 9.4 4700 847 758 9.4 4800 847 774 9.4 4900 848 791 9.4 5000 848 807 9.4 5100 847 823 9.5 5200 847 839 9.4 5300 842 850 9.5 5400 839 862 9.5 5500 836 875 9.6 5600 835 890 9.6 5700 835 906 9.8 5800 834 921 9.9 5900 831 934 9.9 6000 830 948 10 6100 827 960 10 6200 821 970 10.2 6300 815 978 10.3 6400 807 983 10.5 6500 799 989 10.6 6600 791 994 10.9 6700 783 999 11 6800 774 1003 11.1 6900 763 1003 11.2 7000 753 1004 11.2 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).During the prep and machining process, Speed-O-Motive clearanced the bottom end for the Sc Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
