HIGH PERFORMANCE PONTIAC ENGINE-BUILDUP WORKSHEET & SPECS
Bottom End
Block: '74 SD-455
Preparation: Decked 0.020-in, bored, honed, align-honed
Cam Bearings: Dura Bond
Deck Height: 10.210 inches
Crankshaft: Eagle cast-steel 4.21-stroke, PN 104554210
Preparation: Mic'd, balanced
Balancer: Stock
Rods: Eagle H-beam, forged-steel, stock-length, PN CR56625P3D
Preparation: Clean, measure, balance
Bearings: Main, Clevite PN MS-667P; rod, Clevite PN CB-758-H
Preparation: Dress
Pistons: SRP forged flat-top with valve reliefs, PN 149721
Compression Height: 1.480 inches
Preparation: Clean, measure, balance
Piston-to-Deck Height: Zero
Piston Pins: SRP, tool-steel
Method Used to Retain Piston Pins in Pistons: Spiral locks
Rings: Perfect Circle, moly-faced ductile iron (11/416, -11/416, -31/416), PN 315-0032-065
Preparation: File-fit, deburr, clean
Rod Bolts: ARP
Oiling System
Oil Pan: Stock
Oil Pump: Melling high-volume, PN M-54-F
Preparation: Check, clean, weld pickup
Heads
Casting Number: 16 Round-Port SD
Head Mods: Bowl port and polish, milled 0.050 Combustion-Chamber Volume: 98cc
Compression Ratio: 9.49:1
Intake-Port Volume: 206cc
Exhaust-Port Volume: 186cc
Valves, Intake: Ferrea SS 2.11-in, PN F5073
Valves, Exhaust: Manley SS 1.77-in, PN 11355-8
Angles Used in Valve Job
Intake: 30-45-60-75-82-deg
Exhaust: 30-45-55-82-deg
Head Bolts: ARP, PN 190-3603
Retainers: Comp Cams, steel 10-deg, PN 740-16
Keepers: Comp Cams, Super Locks 111/432 10-deg, PN 611-16
Valveguides: Bronze
Valve Seals: PEP, 111/432x0.500
Spring Cups: Comp Cams, 4770-16
Rocker Studs: ARP 71/416-in, PN 235-7204 Rocker Arms: Comp Cams roller 1061-16
Rocker Arm Ratio: 1.65:1
Pushrods: Comp Cams, High Tech, PN 7775-16
Diameter: 51/416-in
Length: 8.650-in
Guide Plates: Comp Cams, PN 4851-8
Cam
Brand: Comp Cams hydraulic-roller, PN K-51-423-9
Duration at 0.050: 224/230-deg
Lift: 0.552/0.561
Lobe Separation Angle: 110-deg
Installed Position: 105.5-deg
Lifters: Comp Cams roller
Valvesprings: Comp Cams, dual, PN 987-16 Seat Pressure: 121 lbs
Open Pressure: 328 lbs
Timing Chain: Cloyes double roller
Induction
Carb: See next issue.
Intake Manifold: See next issue.
Ignition
Distributor: Stock points-type
Coil: Stock replacement
Wires: Stock replacement
Exhaust
Manifolds: Reproduction iron SD
Outlet Size: 2.5-inch
Ancillary Components
Flexplate: RPW, 1845500
Flexplate Bolts: ARP, 200-2904
Plug Kit: Pioneer, PE-115-R
Rear Seal: Fel-Pro, BS-40012
The Melling oil pump was cleaned,...
The Melling oil pump was cleaned, and after a trial fit, the pick-up tube was welded in place.
The factory timing cover on...
The factory timing cover on the SD had seen better days, so a replacement casting was employed. Craig used Dow silicone sealant to guarantee the Super Duty wouldn't leak oil. Once the timing cover was bolted on and the harmonic balancer was installed, the oil pan gaskets and oil pan were installed.
This engine rebuild was designed...
This engine rebuild was designed with a 0 deck, and the final compression ratio poured out to be 9.49:1, approximately 1 point higher than stock. A higher compression ratio is required for throttle response as well as thermal efficiency. During the '70s, the mindset was to lower the compression ratio to limit the oxides of nitrogen (NOx) emissions. NOx is formed as a result of pressure, heat, and exposure time. It's created when the leading-edge, flame-front temperature reaches 2,500 degrees F. Even though the SD-455 left the factory with an EGR valve, the logic then was to lower the cylinder pressure to limit the one mechanism in the NOx equation.
Bob Wise performed a bowl...
Bob Wise performed a bowl port and polish on the rare No. 16 Round-Port heads, followed by a five-angle valve job, all of which was covered in Part I. Reference the impressive flow numbers in a complete flow chart in the sidebar of this story for the actual values. With Fel-Pro gaskets and the heads installed, the head bolts were torqued to 95 ft-lb in the Pontiac-recommended pattern.
A common mistake many novice...
A common mistake many novice engine builders make is forgetting to check the rocker geometry. Craig determined that Comp Cams pushrod (PN 7775-16) would position the roller rocker on the center of the valve stem.
The hydraulic roller lifters...
The hydraulic roller lifters were soaked in lightweight engine oil before installation in the lifter bores.
Butler Performance makes a...
Butler Performance makes a custom valley pan to fit correctly when roller hydraulic lifters are used. The lifter sits up higher, so a stock Pontiac pan needs modification to fit.
When Craig tried to trial-fit...
When Craig tried to trial-fit the stock intake manifold, it was quickly realized that the EGR passage, which sits very low, was hitting the Butler valley pan. In all fairness, this is no one's fault since not many people would run a hydraulic roller camshaft with a stock EGR intake manifold. We are because the original plan was to compare the EFI system to a stock carburetor and intake. The EFI single-plane manifold fits with no problem. We will address this issue in the next installment.
Since we could go no further...
Since we could go no further due to the intake manifold interference issue, we stopped after installing the Comp Cams roller-rocker arms. Bob installed ARP rocker studs. It's very important to choose a stud that will place the rocker-arm trunion in an area that is not cut with threads. Many engine builders don't consider this and suffer a broken rocker stud with a high-lift cam and valvespring pressure. You never want the rocker arm sitting on thread since the cutting process weakens the stud in that region. Check out the next issue for Part III of "New-Age Super Duty."