Small-Bore Pontiac Engine Build - Revenge Of The 350
While most high-performance Pontiac heads are threaded for screw-in pushrod studs, garden-variety 350 castings are not, and must be tapped so the Tomahawk billet steel pedestals can be bolted down. Once installed, lifter preload is set at 0.060, about 1/2 turn of the adjuster. One-piece pushrods are 8.8 inches long and made from 0.080 wall, 5/16-diameter chrome-moly tubing. | 
You already knew this, but sticking a used valley pan on a fresh engine is a great way to pollute it. The hollow chamber usually fills with grime and is almost impossible to clean without the hassle of splitting it open and welding it back together. To solve the problem, try a one-piece rolled aluminum tray from Ken's Speed & Machine Shop. For $35, it's an inexpensive problem solver. A continuous bead of RTV prevents oil leaks. | 
Oiling is provided by a Melling Select Series high-volume pump (PN 10540) and Milodon bolt-on pickup tube (PN 18525). The stock-type pickup is a round press-fit design that's only suited to stock-type oil pans. |
| HPP ENGINE BUILDUP WORKSHEET | | Engine Displacement | 383 | | Horsepower | 462 | | Torque | 436 lb-ft | | Bore/Stroke | 3.905/4.00 | | Block/Crank Combo | 350 Block/428 crank | | Bore/Stroke Ratio | 0.976:1 | | Rod/Stroke Ratio | 1.7:1 | | Bottom End | | Block | '73 350 2-bolt main | | Preparation | Bottom fill with block filler, thermal clean, bore and hone with torque plate, line hone mains with studs, surface to zero deck | | Deck Height | 10.16-in | | Crank | 428 Tomahawk Performance Products crankshaft, 3.00-in mains and BBC 2.200 rod journals | | Preparation | Rifle brush and clean | | Balancer | Professional Products Powerforce Elastamer | | Rods | 6.800-in, Tomahawk Performance Products Ultra-Lites, 756g | | Bearings | King HP series rod bearings std, King AM series main bearings std | | Pistons | Forged, Probe/PPR | | Piston-to-deck Height | Zero | | Piston Pins | 0.990-in, Probe, tool steel | | Method Used to Retain Piston Pins in Pistons | Double Spiro-locks | | Rings | 1/16, 1/16, 3/16 Total Seal, plasma moly | | Preparation | File fit | | Balancing | | Type | No hole balance for less windage | | Specs: | | Piston and Pin | 539.5g | | Piston Rings | 48.4g | | Pin Locks | 4.7g | | Total Rod | 756g | | Rotating Rod | 524.5g | | Bearing | 50.6g | | Bobweight | 1,979.3g | | Oiling System | | Windage Tray | Tomahawk Performance Products, 3/4 stock type | | Crank Scraper | Ishihara-Johnson, Zero-Tolerance Teflon, dual sides | | Oil Pan | Milodon, Road Race, four trap doors | | Oil Pump | 10540 Melling Select High Performance, 60 psi, 3/4 pickup | | Preparation | Inspect prelube |
Milodon just released this beautiful high capacity road race pan (PN 31665). It fits '64-'72 LeMans/GTO models and '67-'73 Firebirds. There are four trap doors surrounding the pickup that resist slosh and prevent oil starvation during braking, acceleration and left and righthand cornering. The low profile side-bustle design provides excellent ground clearance. A Tomahawk windage tray (PN TW $79.95) adds further oil control. | 
Why use corroded original parts when brand new front covers and water pumps are available from PRW Industries? Ken points to the cast-iron pump impeller that moves a greater volume of water than cheaper stamped-steel versions. | 
Design of the new Tomahawk single plane intake manifold was a collaboration between Ken Brewer and Dave Bisschop of SD Performance. Based loosely on the old Holley Street Dominator, they've revised the port contours, eliminated the heat crossover and unnecessary vacuum bosses, and added bungs to accept either EFI or nitrous fittings. Retail price is $199.95. A Holley 770 Street Avenger with #71/#75 jets and WAPP HEI distributor was used for the dyno test. |
| Heads | | Casting Number | #16 small valve | | Chambers | Open | | Head Mods | CNC-Ported at SD Performance | | Combustion Chamber Volume | 77 ccs | | Compression Ratio | 9.6:1 | | Valves | Ferrea 2.08/1.71-in | | Angles Used in Valve Job | Intake: top-30-deg, seat-45-deg, bottom-70-deg;
Exhaust: top-30-deg, seat-45-deg, bottom-75-deg | | Mods | CNC-Porting | | Retainers | Manley | | Keepers | Comp Cams | | Valve Guides | Bronze liners | | Valve Seals | Viton Rubber | | Rocker Arms | Tomahawk Performance Products Rocker Shafts System, 1.6:1 roller | | Pushrods | PRW chrome moly | | Diameter | 5/16-in | | Length | 8.800-in | | Head Bolts | ARP | | Cam | | Brand | Crower hyd. roller | | Duration at 0.050 | 234/242-deg | | Lift | 0.549/0.573 | | Lobe Separation Angle | 112-deg | | Installed Position | 108-deg | | Lifters | Crower hyd roller | | Valve Springs | Crower double | | Seat Pressure | 130 lbs | | Open Pressure | 330 lbs | | Timing Chain | S/A 9 Keyway true roller with removable bronze bushing |  Mounted on the PPR 1,500 horsepower Dynomite dual rotor dynamometer and exhaling through a set of Doug's D564 '64-'67 GTO headers, over 20 pulls were made on the fresh 383. Peak readings were 462.6 horsepower at 6,090 rpm with 436.2 lb-ft at 4,389 rpm. All of this was on 91-octane pump gas with the ignition timing set at 34 degrees. | Induction | | Carb | Holley Street Avenger, 770 cfm, vac sec, | | Jets | #71/#75 | | Fuel Pump | Dyno Pump/Magna Flow 500 gph | | Fuel Regulator | AeroMotive High Flow | | Fuel Lines | 1/2 and 3/8 | | Intake Manifold | Tomahawk Performance Products, single-plane | | Mods | None | | Ignition | | Distributor | WAPP HEI | | Wires | Dyno/ACCEL Graphite for no computer interference | | Total Timing | 34-deg | | Initial Advance | 13-deg | | Exhaust | | Headers | Doug's | | Primary Tube Diameter | 1.75-in | | Collector Size | 3.00-in | | Cylinder Head Flow | | Lift | Intake CFM | Exhaust CFM | | 0.100 | 71.7 | 59.1 | | 0.200 | 143.8 | 107.8 | | 0.300 | 197.2 | 147.1 | | 0.400 | 233.6 | 174.9 | | 0.500 | 248.4 | 197.7 | | 0.550 | 255.7 | -- | | 0.600 | -- | 212.7 |
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