[lust4speed]

I think BOP's advise on an in-car replacement with their seal is only recommended on the 3" mains. The 3-1/4" mains have to have the anti-rotation holes filled with silicone which is pretty near impossible with the crank blocking access to the holes on the 421, 428, 455 blocks.

I've done two rope seal replacements for friends lately. Both 455's. Engine upside down on the engine stand with the pan and timing cover, timing chain, main caps, and rod caps removed. Push the pistons down until they touch the head. Crank will lift right out if your back is up to it. Then you have all the room you need to do the job correctly.

Putting the crank back in is a little more tricky. No matter how the crank is positioned, two of the rod journals will hit the ends of the rods. It helps to have an additional set of hands, but one person can do it. The offending rods must be held in position aligned with the two rod journals while the crank is lowered into position. Install these caps first, then eyeball the rods and pick which ones have to install next. I seem to always have to lift the crank about 3/8" to swing one of the rods into position so it can be installed. The remainder of the rods will pull right up to the rod journals.

I use Ultra Gray to seal up the tips of the rear main cap and on the rear of the pan. Seems like we've had an epidemic of leaks dripping out the alignment holes on the rear, or maybe I'm getting all the fix-it calls. Seems like it is about 50/50 on whether the seal is leaking or the gasket around the rear main is leaking. Whether you have the early style cap with the groove or the flat late style, waiting at least overnight for the sealant to set up is the way to avoid the gasket leaking. I think that most of the pan gasket failures are caused by adding oil before things set up. This allows the oil to get under the sealant and breaks the bond. Once it is dry (I'm now waiting a full 24 hours), it creates a super bond with the metal. This area is just about the only place on the engine I use silicone, and I use enough so some is squished out and forms an additional boundary between the seal and oil.

Here's one of the engines ready for the crank to go back in. You have to look to see the rods after they have being pushed down out of the way.