Remove the rocker arm covers and valve train. Before removing the pushrods, fabricate a cardboard box with numbered holes to keep them in their original sequence, then remove the pushrods and place them in the box. Next, remove the distributor and the intake manifold. If a Lash Adjuster removal tool such as Dodge/Plymouth No. C-4129 is available, slide it through the opening in the cylinder head and seat it in the Lash Adjuster to remove the Lash Adjusters, or alternatively, use a small scribe to reach through the cast hole. Ensure the Lash Adjusters are kept with their respective pushrods for proper installation. Proceed to remove the oil pump, distributor drive shaft, timing chain and gears, and the camshaft thrust plate, noting the position of the oil tab. Install a long bolt in the front of the camshaft to facilitate removal, then carefully extract the camshaft, avoiding damage to the cam bearings. Lubricate the camshaft lobes and bearing journals before installation, and insert the camshaft to within two inches of the installed position in the engine block. Insert a tool behind the distributor drive gear to prevent the welch plug in the rear of the engine block from being knocked out, leaving it in place until the timing gears and chain are installed. Install the camshaft thrust plate and chain oil tab, applying engine assembly lubricant to the thrust plate mating surface and ensuring the tang on the oil tab engages in the thrust plate hole. Tighten the thrust plate mounting bolts to the specified torque, and complete the installation in reverse order of removal, applying engine assembly lube to the valve and pushrod contact surfaces and lubricating the Lash Adjusters with motor oil before installation.