I'll throw my hat in the ring too, if you end up doing a full rebuild of the engine and want to turn it into a 3.0l engine with more power (not visual to the eye) in the process. I have been very satisfied with the results on my 280SL/ 3.0 project, that I have developed and tested for the past two years. The cost would be very comparable if not less than a Metric Motors engine. My engine uses a custom (modified MB) crankshaft and custom forged pistons and otherwise all original MB hardware.
Best, Tom Colitt
(located in Los Angeles)