Followthe manufacturer's torque sequence on the head bolts. This will have youworking up to final torque in three stages and working from the centerof the head toward the outside. Install a rocker arm of your choice.There are stock rockers, aftermarket rockers that look like stock,roller tip, and full rollers to choose from. If your original rockershave worn grooves on the valve stem contact face, they should bereplaced. Aftermarket stock-appearing rockers such as Comp Cams PN1212-16 would make a good replacement for the stock parts. They have thecorrect 1.5:1 ratio rather than the stock 1.46:1. This will give you alittle more valve lift. Let your pocketbook and the rules be your guide.
PUSHROD LENGTH: Since we have mixed, matched, and milled some parts, weneed to be sure to use pushrods of the correct length. With the manifoldstill off, set the pushrods in place. Turn the cam so that the lobe youare checking is on the back side of the high point (valve closed). Aninexpensive plastic gauge is available from JR Motorsports, PN prc 1038,to check pushrod length. When the gauge is slipped over the rocker armstud, it should contact the valve stem and the pushrod at the same time.Having a pushrod of the incorrect length can reduce power and lead tovalvetrain failures.
INSTALLING THE INTAKE MANIFOLD: Before you install the intake manifold,check to make sure you installed the distributor drive rod. It can stillbe installed from the top, but without the plastic sleeve that preventsit from falling out when you remove the distributor. All is not lost solong as you remember not to jerk the distributor out. Remove it slowlyand carefully and you will be OK.
The intake manifold gasket set has twogaskets and two rubber snakes. Toss the snakes. Again, clean the gasketsurfaces to make them oil free. The two gaskets can be put in place.Using a silicone sealant, smear a small dab around the water passages onthe manifold. Using this same sealer on the ends of the block, lay downa line about 1/8 inch high; don't overdo it. Sealer that is squeezed outon the inside of the engine can find its way to the oil pickup screen.When the screen becomes blocked, instant catastrophic engine failurewill occur.
Carefully lower the intake manifold in place. Don't move itaround. This avoids disturbing the gasket and sealer. With all themanifold bolts in place, begin tightening from the center workingoutward.
In the stock cast iron manifold...
In the stock cast iron manifold shown in the photo, the arrow points to the bolt holes where the manifold bolts to the head. These are perpendicular to the mating surface.
This photo shows the manifold...
This photo shows the manifold bolt holes in a Vortec head. Notice that the bolt holes are drilled and threaded at an angle to the mating surface. These holes must be redrilled and threaded before a stock cast-iron manifold can be used. This is often necessary because car and truck engines with Vortec heads were nearly always angle-drilled for fuel injection rather than the carbureted manifold required in many classes.