[JSchmitz]

Let me start at the beginning. I, like Cliff Ruggles, had trouble getting the rear main to seal in my '70 455. Like Cliff's, mine would only leak after a short drive. My engine builder, Jim Moran @ MBJ Machine, put in a Cadillac seal during the rebuild. This was prior to the B.O.P seal being available. I had a leak. I pulled the engine. I found the rubber rear pan gasket split. So, I figured it was a bad rubber gasket. I put in a new rubber gasket. It still leaked. I pulled it again. I found another split rubber seal. I'll fix that (I thought). I put in a cork gasket. It still leaked. I pulled the engine again. Now I figured it had to be the rear main seal. Jim had never had a Cadillac fail before. (My luck!) I had some old style rope seals laying around. So, Jim put one in for me. It leaked slightly. But nothing near the Cadillac seal. I recently pulled my engine chasing a strange noise. I checked the bearings while I had it out. I figured the rope seal would be a long shot after being separated. I decided to give the B.O.P. seal a try. I drove it today for about a half hour. It hasn't leaked a single drop!!! Thank Wade!!!

I would like to add some of my observations and techniques while I'm at it. First is the groove in my block. I haven't examined any other 455 blocks. So, I don't have anything to compare with. However, the groove in my block was very inconsistent and rough. It was much wider (for and aft) on one side than the other. The cap was a lot better. I was afraid the ends might not align with each other. Secondly, I'll outline how I installed my seal. I tried filing the seal ends as suggested in the instructions. I wasn't happy with the finish or squareness of the ends. I ended up using my belt sander to dress the ends. This produced very clean square ends. I used Ultra Black rtv to fill the anti-rotation holes in the block. I also put a thin layer on the back of the seal (Contrary to the instructions). The groove was so rough that I was afraid of oil going around the seal. I put a thin layer of sealer on the ends as well. I don't recall if I used black or red on the ends.

[machine shop tom]

Thank you for posting you results. A customer just picked up a 389 that I machined the block and KRE heads, as well as balanced the rotating assembly. He will be assembling it and purchased the BOP seal for that application. I sure hope he is as capable in installing the seal as you were. I also will be finishing a 455 build and will sell that customer a BOP seal for that block.

tom