Rebuilding a Slant

If it has good compression, why would you need a rebuild? Confirm first. If the goal is just replacing seals and gaskets, that can be done w/ engine in-car and I have seen the gasket set for ~$30 on ebay. The rear seal in a slant is a split 2-piece ring. It is in a separate aluminum holder. You push the upper half around. You can also change all the rod and main bearings while the oil pan is off. I recall front & rear seals are same PN as for the 426 Hemi engine. When you remove the front timing cover, expect the chain and sprockets to need replacing (~$30 set). Of course, a good time to consider a cam and lifters swap. You can get better quality silicone gaskets from "Real Gaskets" (TN). Still assuming good compression, the only reason to remove the head is if the valve guides are worn, but oil sucked into the intake at idle is usually fixed by replacing the rubber umbrella seal over each valve. Read how to avoid dropping a valve into the cylinder. Also, replace the rubber seals on the spark plug tubes. rockauto should have everything you need.