I am in the process of rebuilding a B-20 which will go into my 122 wagon. I was told I should get the ipd front and rear main seals modified to take the modern, rubber seal rather than the felt ring. Someone else then told me that, for the rear, I could get a housing off a late B-20 and it would already have the new style seal. I found a rear seal off a '72 B-30, which takes the new style seal and which fits my B-20. My question, the old housing has a drain hole in the middle which allows oil to drain into the sump and the B-30 housing does not. Is there any reason not to use this housing with a new seal on the B-20? I would appreciate any comments anyone has. Alan Kelly