Using tools from Powerhouse, we installed our new Comp Cams street roller grind (PN 11-770-8). This cam features 236/242 duration at 0.050 and 0.647/0.654 lift and a 110-degree lobe separation angle. Even with this mild grind our baby Rat was still able to pull 16-inches of idle vacuum and pump out over 500 hp.
With the cam and pistons installed we bolted the oval port Brodix aluminum heads on. These lightweight castings come with 2.25/1.88-inch stainless steel valves and we added Comp Cams (PN 938) springs and valvetrain hardware with Comp's 1.7:1 aluminum roller rockers. Some of rocker arm stud holes go right through into the intake ports so those studs must be sealed with thread sealant or else oil will be sucked into the engine.
The Brodix heads feature a 119cc combustion chamber that, combined with our Speed-Pro forged pistons and Fel-Pro head gaskets gave us a final compression ratio of 10.25:1. Just within the limits of street gas with aluminum heads. We installed the heads with the unmodified chambers as shown here. You can also see the Autolite No. 53 spark plug's electrode tip just protruding into the chamber, which is just right.
Moving up to the top of our assembled long-block, we bolted on an Edelbrock Performer RPM Air Gap intake manifold and poured 30-weight motor oil in, drenching the rockers and springs at the same time.
Anytime you install steel fittings into an aluminum part you must use anti-seize. We apply it sparingly to the spark plug threads, careful not to get it past the last thread where it could be exposed into the chamber.
We'll be dyno testing this engine in the morning, so we primed the Moroso oil pump using a converted HEI distributor base and shaft driven by a 1/2-inch drill. Make sure to slowly rotate the crank while priming the oil pump to ensure the entire motor gets lubed.
To seal our trick GMPP cast-aluminum valve covers; we relied on Fel-Pro's new blue valve cover gaskets. These steel-cored silicone rubber coated beauties feature steel compression sleeves in the bolt holes to keep over-zealous bolt tighteners from crushing the gasket.