Last month, we started part 1 of the story of 15-year-old Hunter Hay and his dad, Ron, building a 408ci LQ9 stroker engine to run in a drag ’n’ drive 1966 Nova when Hunter turns 16. In part 1, Dunsworth Machine of Enid, Oklahoma, balanced and blueprinted the LQ9 stroker short-block, then Ron and Hunter gathered up the Summit Racing Pro LS 6.0L rotating assembly (PN SUM-R24400308). Dunsworth finessed and carted the LQ9 home in kit form where Ron guided Hunter how to build a high-horsepower engine to endure thrashings.
In last month’s issue we covered Dunsworth Machine blueprinting the short-block and Hunter assembling Summit Racing’s Pro LS 6.0 4340 forged steel crank rotating assembly.
Shane Dillon at Dunsworth knocked the cam bearings in then Hunter fed Summit Racing’s cam (PN SUM-822R1) into the block. In part 1 we focused on the short-block going together but disclosed that Hunter and Ron completed the 408ci LQ9 right up to installing a pair of Trick Flow heads (PN TFS-3061T002) straight from the box.
The threads in the LQ9 block were chased clean prior to hand-tightening the ARP Ultra-Torque lubed (PN ARP-234-4317) head studs.
We concluded part 1 with Ron and Hunter returning the completed engine back to Dunsworth Machine to make a dyno pull to break in the cam and make sure the engine didn’t have any problems. With only 21 degrees advance and a four-barrel carb, the results were 580.9 hp and 545.1 lb-ft of torque. Not bad since extracting the maximum amount of horsepower wasn’t the goal in that state of tune.
Pre-soaked in oil, Summit Racing ZDDP Performance 10W-30 motor oil to allow the oil to seep inside and ensure the lifters would “pump up.”
In part 2, our focus is returning to the photos we took of the top-end going together during the time Hunter and Ron were building the LQ9. At the end of part 1 we teased the possibility of capping the LQ9 off with a ProCharger supercharger because at that stage it was only a dream.
Sourced from Summit (PN 12595365) genuine Chevrolet LS valve lifter guides followed inserting the hydraulic lifters.
Enter Hunter’s grandpa, Harold “Papa” Clay, with an early Christmas present for Hunter: an F-1A-94 ProCharger supercharger complete with a 1LS400 LS Accessory drive kit. A few weeks after Christmas 2024 Hunter and Ron were back at Dunsworth Machine to make a few dyno pulls with the supercharger installed. Blowers and turbochargers amongst gearheads are often referred to as power adders, but after dyno testing the 408ci LQ9 and producing nearly twice the amount of horsepower we’re calling the ProCharger a “power doubler.” The key to extracting the horsepower was tuner Jonathon Lorg downloading Holley’s program for the Holley EFI management system (PN HLY-554-114) and manipulating the data logging from setting the idle for the Holley drive-by-wire pedal (PN HLY-145-160) to achieving maximum power. The results with a 5-inch pulley, 16 pounds of boost and 18 degrees advance, the blown LQ9 produced 1,025.3 hp and 822.9 lb-ft of torque.
Great for a boosted LS-type engines (PN BTC-BTR22033-2), LS9 head gaskets were installed as-is without applying any type of sealant.
Is building a 1,025hp 408ci LQ9 something that can be repeated by the average DIY guy at home? All the parts from the stroker kit to engine oil were mail-ordered from Summit Racing and were not modified in any way, so that’s a “yes.” The tricky part is finding a machine shop like Dunsworth Machine that is capable of precision work and has testing facilities. That’s not exactly a “no,” that’s a “maybe.”
The Trick Flow (PN TFS-3061T002) aluminum cylinder heads were guided down perfectly level to avoid hanging up on the ARP head studs.When installing the ARP head bolt washers, it’s important the smooth side of the washer faces up and ARP Ultra-Torque fastener assembly lubricant is applied liberally.The torque setting and correct sequence to torque down the Trick Flow heads is specified in the instruction sheet.Harland Sharp SLS17 roller tip rocker arms were used. With numerous upgrades from a stock LQ9, such as decking the block, new cylinder heads, and thicker head gaskets dictated adjusting the pushrod length.To set the preload for (PN SUM-HT217-16) Morel high-performance lifters, Hunter measured the stock pushrod length as a starting point to adjust the Trick Flow pushrod length checker.The Trick Flow pushrod length checker is calibrated. Each full rotation equal 0.050 inch. Grooves on the inner sleeve keeps count of the number of rotations made, or measure length with dial calipers.Summit Racing (PN SUM-14917500) HDR thick wall seamless chromoly pushrods (11/32 indicates tube diameter and 7.500 indicates length). Shorter-length pushrods, 7.400 for example, use PN SUM-14917400.Final assembly of the roller tip rockers included a liberal coating of Lubriplate No. 105 on the threads and pushrod cups and tips.The lifter valley gasket (PN SUM-G2629) is installed without applying a sealant.After installing the Summit Racing billet lifter valley cover (PN SUM-240055B), the four corner steam kit (PN SUM-220950B) was plumbed to the Trick Flow heads to vent steam pressure.Mounting the ProCharger LS accessory drive kit starts at the left bank (driver side) utilizing existing factory boltholes in the cylinder head and block.Summit’s (PN SUM-918019) billet engine stand adapter makes short work out of mounting the block to the stand.The alternator bracket mounts to the Trick Flow head and the mounting bracket for the ProCharger supercharger with supercharger tensioner pulley.This side view shows the alternator two-hole spacer prior to tightening in place. A 2007-13 GMC or Chevy truck alternator fits.ARP bolts throughout the water pump are bolted into place after the alternator and ProCharger mounting brackets but before mounting A/C bracket assembly.Belt slip means lost horsepower, so the decision was made to upgrade from an eight-groove serpentine belt to a 10-groove belt. Installing an ATI Super Damper is perquisite for 500-plus horsepower.The 10-groove pulley for driving the supercharger and six-groove pulley works good for driving a Vintage Air A/C compressor.The two M8x 100mm bolts must be inserted into the A/C compressor before mounting.A Sanden SD-7B10 A/C compressor was used for proper belt alignment and fitment.ProCharger (PN 1LS400) LS Accessory drive is engineered to tuck the F-1A-94 ProCharger as tight to the engine as possible. Equipped with a Tick Performance intercooler and Holley Hi-Ram intake, the Nova will be fitted with a 4-inch cowl hood.It looks like Hunter’s 408ci LQ9 has never been run, but as pictured here it’s the veteran of several unblown and blown dyno pulls.Blown and injected induction is a Holley EFI LS Hi-Ram intake manifold with 220-lb/hr Siemens Deka Low-Impedance Extreme Flow injectors and AC Delco 19420707 throttle body.Gary Dunsworth said another 75 hp could probably be coaxed out of the blown engine, but 1,025 hp will be plenty enough move Hunter and his Nova down the strip and driven to high school.
