The ZZ4 block comes already machined for the factory LT1 cam retainer plate. This plate keeps the roller cam from walking forward in the block. With a flat tappet cam, the spinning motion of the lifters keeps the camshaft from moving forward, but with a roller cam you need a retainer of some sort to keep the cam from moving. On a standard Gen I small-block cam/timing set, you use a button spacer to do the same thing.
For the camshaft sprocket bolts, some high-strength threadlocker is good insurance to keep the bolts from coming loose due to engine vibration. There are also special retainer tabs that go under the bolts with 'ears' that you bend back to keep the bolts from loosening also.
When installing your timing chain, make sure the dots on the cam sprocket and crank sprocket line up across from each other. If they don't, the cam will be out of phase/timing with the crankshaft and the engine will run like garbage, and possibly bend a valve or two.
Moving to the bottom of the engine, we installed a new standard-volume oil pump. Why not a high-volume pump? Most street engines have zero need for a high-volume oil pump. Usually the increased oil flow/capacity of an HV pump is only needed in racing applications. On the street, an HV pump can make too much oil pressure, which will drag down the engine, hurting power output and possibly causing damage. Unless your engine is seeing a lot of sustained high rpm operation, a standard volume oil pump is all youll need. To secure the pump, we used an ARP oil pump stud kit. Capping the bottom end off was a standard small-block oil pan from GM Performance.
With the cam and lifters installed, it's time to install the heads and top of the valvetrain. First up is the head gasket. Each gasket is stamped with "this side up" so you cant put them on the wrong way. To assemble the engine we ordered a full engine gasket kit form GM Performance's catalog.
To bolt down our GM Fast Burn heads, we used ARP's stainless head bolt kit, PN 434-3601. Why stainless? Besides the normal salt air on the Florida coast and stainless steel's corrosion resistance, we're addicted to shiny objects, and the stainless bolts have some extra pop over the normal black-oxide treated head bolts. Since some of the head bolt holes go into the water jackets, thread sealer is necessary. To play it safe we put thread sealer on all of the head bolts. To install them you'll need a good torque wrench and deep-well socket. Install all of the head bolts and just hand tighten them. After that, go back and tighten each one in sequence in a 25-50-68 lb-ft increment. So, first you'll tighten all the bolts in sequence to 25 lb-ft of torque, then 50, then 68. If you dont, you'll warp the heads and won't have proper sealing, equaling no/low compression.
Instead of ZZ4 heads, we chose to go with GMPP's Fast Burn heads, PN 12464298. They feature 210cc intake ports to the ZZ4's 163cc ports, larger 62cc combustion chamber, and has dual intake bolt patterns, so you can either use a Vortec-style manifold or a Gen I manifold with these heads.
Another advantage the Fast Burn heads have over the ZZ4s is the use of the Vortec/LT1/LT4 style combustion chamber with some tweaks to maximize combustion, resulting in higher cylinder pressures and more horsepower. They have 2.00-inch intake valves and 1.55-inch exhaust valves, screw in studs from the factory, and will use either center-bolt or perimeter-bolt valve covers.
With the heads installed, next up were the rockers and pushrods. We used GMPP's heavy wall 3/8-inch pushrods and 1.5 ratio, self-aligning aluminum roller rocker arms. You can also use the old reliable stamped steel rocker arms on these heads if necessary. Be sure when installing the pushrods to put a dab of engine assembly lube on the lifter end of the pushrod. For the rockers, put some lube on the roller tip and the pushrod adjuster cup.