Keep in mind that as you change engines you can get different intake, exhaust, and linkage configurations which could make the swap more difficult and expensive. Also, when you change the engine "family" you will probably need a different transmission and that could mean changing the length of the driveshaft, as well as mount location, linkage, coupling, etc.

None of these are show-stoppers, but they are likely to add time and expense to the point where $200 pistons look attractive.

Personally, I think a later injected 6-cylinder (M110, M103/104) would be totally cool.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe