When we last discussed our Project Pure Poncho 455-based 467ci stroker engine, Craig Wise at Racecrafters had assembled the bottom end. We will pick up the assembly process in this issue and complete it in preparation for dyno testing.
With the Mr. Gasket high- clearance chrome valve covers (for the roller rockers) and Pontiac silver-blue metallic paint, our mule looks just about ready to challenge the Stuska dyno water brake!
To review, this mule engine is being built to test parts combinations in HPP. Bob and Craig Wise at RaceKrafters Automotive Machine have offered their services and will be using their Stuska dyno for future testing. Summit Racing Equipment provided most of the parts for this buildup except for the stroker reciprocating assembly and timing cover and valley pan that Butler Performance contributed.
The whys and hows of the parts choices for the initial combo were discussed in the last issue, which can be found using the keywords Project Pure Poncho in the search. Suffice it to say, we wanted to build a pump-gas engine that readers could relate to. We’ve included the engine buildup worksheet in this installment as well, so you can reacquaint yourself with the combo. Follow along as we complete the assembly, and please keep in mind that photos were taken during pre-assembly and assembly, so there may be instances where installed parts are seen in one photo and not the next.
1 This Butler Performance reproduction timing cover was beautifully cast and is a good investment over a worn 40-year-old piece. It fits ’69-’79 engines with the 11-bolt water pump. To mount the Summit Racing Street & Strip Competition steel harmonic damper, Craig used a damper-installer tool and some Sunnen press lube on each side of to reduce the chance of galling, and then he torqued the bolt to the required 160 ft-lb.
2 The damper is SFI-approved and features engraved timing marks for easy tuning. Summit says that the special bonded elastomer will transfer heat more quickly than a stock damper making it beneficial for high performance applications. Craig then indicated TDC on the No. 1 cylinder to confirm the timing marks. The Summit damper and Butler Performance timing cover were perfect.
Correction to the bottom-end story in the last issue: Photo #21 of the oil pan installation is out of order in the story. It should have been placed after the cam degree sequence #22-#23 and short-block photo #24. Sorry for the inconvenience.
HPP Engine Buildup Worksheet
Engine Displacement: 467 ci
Bore/Stroke: 4.185 / 4.250-in
Bore/Stroke ratio: 0.98:1
Rod/Stroke ratio: 1.6:1
Bottom End
Block: Stock ’75 455
Preparation: Cooked, magged, line-bored, line-honed, decks squared with BHJ, bored and honed with torque plates
Deck height: 10.205-in
Crank: Butler/Eagle forged
Preparation: Balanced, polished
Balancer: Summit Street/Strip, steel, elastomer, 6.610-in, SFI 18.1
Rods: Eagle forged H-beam, 6.800-in
Preparation: Pin end honed to proper size, balanced, big end checked for proper size
Bearings: Clevite, plain shell, tri-metal
Preparation: Clean, check for proper clearance in rods
Pistons: Butler/Ross forged flat-top with valve reliefs
Preparation: Pin-fit, check size, clean
Piston-to-deck height: 0.010 below
Piston pins: Ross, 0.990 floating, 0.155-in wall
Method used to retain piston pins in pistons: Spiro Locks
Rings: Total Seal, moly top, ductile second, three-piece oil; 1⁄16, 1⁄16, 3⁄16-in
Preparation: File-fit, clean
Rod bolts and head bolts: ARP
Balancing specs: Internal
Oiling System
Windage tray: Canton in pan
Crank scraper: Canton in pan
Oil pan: Canton Racing Road Race Series 5-quart, wet-sump
Oil pump: Melling M54DS high-volume
Heads
Casting number: 6X
Combustion chamber volume: 96.2 ccs
Maximum flow at 28 inches of pressure
Lift Intake Flow CFM Exhaust Flow CFM 0.100 66 55 0.200 133 106 0.300 191 149 0.400 224 70 0.500 236 182 0.600 250 186
Compression ratio: 9:1
Valves: Manley SS 2.11/1.77-in
Angles used in valve job:
Intake: 45, 60, 75, and 82 deg, 82 is hand-blended into 75 deg.
Exhaust: 45 deg, 12mm radius
Retainers: Comp Cams, steel, 10-deg beehive
Keepers: Comp Cams 10-degee, 11⁄32-in
Valve Guides: K-line bronze liner
Valve Seals: Steel/Viton
Rocker Studs: ARP 7⁄16-in
Rocker Arms: Comp Cams aluminum full roller, 1.65:1
Pushrods: Manley 3⁄8x8.900-in
Cam
Brand: Comp Cams Xtreme Energy hydraulic roller
Duration at 0.050: 224/230-deg
Lift: 0.552/0.561-in
Centerline: 106-deg
Lobe Separation Angle: 110-deg
Installed Position: 106-deg
Lifters: Comp Cams roller
Valvesprings: Comp Cams Beehive
Seat Pressure: 137 lb/in
Open Pressure: 290 lb/in
Timing Chain: Comp Cams double-roller
Induction
Carb: Holley 4150 HP 750-cfm, mechanical secondaries
Intake Manifold: Edelbrock Torker II
Ignition
Distributor: MSD Pro-Billet Ready-to-Run
Exhaust
Headers: Hooker
Primary Tube Diameter: 1.75-in
Primary Tube Length: 32.00-in
Collector Size: 3.00-in
Gaskets
Brand: Fel Pro
