RaceKrafters 467ci Stroker - Project Pure Poncho

[3] RaceKrafters designed and manufactured a splash shield specifically for Pontiac engines. Craig says, “The long-stroke crank throws a lot of oil into the lifter valley, so this part helps keep it in the crankcase. It also serves to block large pieces from dropping into the bottom of the engine should there ever be a valvetrain failure.”

[4] Moving to the cylinder head installation, the Fel-Pro head gasket is shown in place. The deck height of the block was set at 10.205 inches, which put the piston 0.010-inch down in the bore. With a head gasket volume 9.5 cc’s, a 96.2cc combustion chamber, and valve reliefs, the compression ratio is 9:1.

[5] The 6X cylinder heads were fully ported by Cory Porter and fitted with Manley 2.11-inch intake and 1.77-inch exhaust valves—larger than the stock 1.66-inch exhaust valve. Craig explains, “We upgraded the exhaust valve size for two reasons: 1) It allows for the removal of more material to repair the valve seat area; 2) It allows for more bowl area under the valve to improve flow.”

[6] Craig removed the Comp Cams valvesprings on one cylinder and installed checking springs to take geometry and clearance measurements.

[7] With the gasket in place, Craig lowered the head onto the block over the dowels and installed the head bolts temporarily.

[8] To improve valvetrain durability, Craig had Cory previously modify and install BBC 7⁄16-inch studs. He placed a 7⁄16-inch washer under each stud to ensure the trunnion of the Pontiac rocker runs on the shank of the stud and not the threads (the weakest part). He then removed 0.300-inch of the thread length, so that the rocker’s set-screw has maximum thread engagement.

[9] Using a checking spring and an adjustable length pushrod to determine the pushrod length, Craig rotated the crank to get the cam on its base circle and installed the rocker arm and set it up so it’s nearly centered on the valve stem. Then he rotated the crank through the cam’s full lift while watching the sweep of the rocker arm. He says that to keep it as centered as possible throughout its travel, sometimes the rocker needs to start a bit off-center toward the lifter valley. When it’s in the center through its travel, the full lift of the cam is realized. If it’s too off-center, lift is reduced and the valve gets high side loads and prematurely wears the guides. The required pushrod length was 8.900 inches.

[10] To check piston-to-valve clearance, Craig rotated the crank to come up on the cam’s overlap and stopped at 10-degrees BTDC to check the exhaust, and then rotated 10-degrees AFTDC to check the intake. To perform the check, he used a dial caliper each time to measure from the retainer to the valvespring seat, he then pushed the valve rest of the way open to touch the piston and measured the same area. He subtracted the second measurement from the first to get the clearance, which was over 0.250 inch.

[11] The head was then removed and Craig replaced the checker springs with the valvesprings and installed both cylinder heads. He used ARP grease under the bolt heads for an accurate torque reading and torqued them, starting in the center and working outward in an X-pattern for the sequence, in two increments—50 ft-lb and then 95 ft-lb.

[12] He coated the Comp Cams roller lifters with 30-weight oil and installed them. Then he put in the Manley pushrods through the Comp pushrod guideplates and seated them in the lifters.

[13] Craig set the valve lash at zero plus a quarter-turn preload. These Comp Cams roller rockers feature needle-bearing trunnions to allow for valvespring loads over 350 pounds and are made from aluminum alloy.

[14] The Butler Performance billet-aluminum valley pan provides the clearance needed to run our hydraulic roller lifters. We chose the PCV-style, which uses a double-baffle design to thwart oil consumption through the PCV. When installing it, he warns not to over-tighten the hardware—as he has seen people do in the past—because it can distort the pan. He uses a pair of jamb nuts on each stud just below the height of the front and back sealing flanges of the block to act as a positive stop.

[15] Cory port-matched the Edelbrock Torker II manifold prior to installation to compliment the massaged 6X cylinder heads. Craig and Bob specified this manifold: “It has the cross-sectional area to match head flow and displacement.” Craig first test-fit it without the front seal and then with it to ensure that the recess in the intake was deep enough and bolt holes lined up. When he installed it, he used Locktite Aviation gasket sealant (PN 30516) on the gaskets and on the bolt threads so oil can’t wick up. He inserted all of the bolts and just started to thread them in. He then tightened the front bolt at the water pump to draw the intake forward just a bit to make that front seal, well, seal. He then torqued the bolts to 20 ft-lb in a crisscross X-pattern working from the center out.

[16] For ease of operation and tuning on the dyno, Craig and Bob chose a carb with some race features. The new model 4150 HP Holley mechanical secondary 750-cfm carburetor lacks a choke horn for the street, but does have threaded air bleed adjustments to make tuning easier. Other features include: smoothed venturi transitions for increased airflow, stainless steel throttle plates, notched floats, and Dominator style fuel bowls so the fuel line can be attached to either side. MSD’s Pro-Billet Ready-to-Run 6061-T6 aluminum distributor is easy to install with just a few wire connections, it has a maintenance-free magnetic pickup to trigger the ignition, eliminating points, and has an adjustable mechanical advance, not to mention other features to increase output and durability. The as-delivered setups of the carb and ignition will be used to break in the engine.

[17] Craig installed the Edelbrock water pump with the plate, coolant transfer tubes, seals, and gaskets using the aforementioned gasket sealant. Edelbrock says its Victor-series aluminum, high-volume water pump’s CNC-machined housing has one-way internal passages designed to increase coolant flow at higher velocities, even at low engine speeds. Large curved-vane, CNC-machined, cast-iron impellers are also said to increase flow with less cavitation. Though not of paramount importance for dyno pulls, all of these features will be better utilized once the engine is installed in the car.