50s Hemi Engine Build With 21st Century Technology - A Contemporary Chrysler - Tech

Since the motor is going back together for the first time since being machined, it's important to check all the clearances. This can be done by either measuring them with a snap gauge and an outside micrometer with the bearings installed and the main cap torqued to spec...

...or by installing the crank with all the mains torqued to spec and Plastigaging the surfaces. Main bearing clearances should be between 0.0005-0.0015-inch.

The rear main bearings are block and cap specific, mix them up and you'll starve the rear main for oil. Also notice the locating ring for the rear main cap, this aligns the cap to prevent the oil pump driveshaft from rubbing against the block.

Originally, the rear main cap featured a rope seal to prevent oil from leaking out into to the bellhousing. A seal from a 440 Mopar is now a common replacement. The rear main cap also has a provision to drain oil back to the pan between the bearing and the seal.

Originally, the rear main cap featured a rope seal to prevent oil from leaking out into to the bellhousing. A seal from a 440 Mopar is now a common replacement. The rear main cap also has a provision to drain oil back to the pan between the bearing and the seal.

With the clearances checking out and the bearings bathed in a healthy dose of engine assembly lube, the mains are torqued to 85 ft-lb. Note the adapter on the rear main cap that accepts a high-volume, small-block Mopar oil pump from Hot Heads.

Here's the small-block Mopar oil pump installed on the adapter. These are commonly available and provide more volume than the original Hemi item.

The pump registers on the main cap and requires another adapter to align the pump driveshaft with the block.

Moving onto the rest of the rotating assembly, the first thing to check is the piston ring endgap. The ring is installed an inch or two into the bore and the gap is measured using a feeler gauge. Ring gap minimum is 0.015 inch and shouldn't be over 0.025 inch. If the gap is below tolerance, it needs to be filed using a ring jig tool.