BPB,
If you can rebuild a SBC why don't you try a SB Ford and stick it into an sl/slc? You will not only end up with an engine with a lot more HP but one that you can afford to drive and maintain. SBC are a bit too wide in the V and the bell housing is a bit large to fit into an sl/slc but I understand that the V on a Ford engine is slightly narrower and might be easy to fit in. There are a lot of really good engines out there, some like the new Chrysler with ohc, that might be easy to adapt. Even many V-6s now a days have upwards of 250 hp which would make an sl/slc mive right along.

Unfortunately you won't get your money back out of either a rebuilt MB or a Ford swap but the experience might be interesting. If you did an American V-8 you might document it. I bet that there are more people out there besides myself that would be interested in the project. This could be the very winter project that you have been looking for.