Hi Joe,
About point 2-Revs: According to Günter Engelen's book, 230 SL 4 speed manual Euro version (with the standard rear axle-drive ratio 3.75) has a fourth gear of 31.4 kmh every 1.000 rpm (19.5 mph every 1.000 rpm), so at 65mph (104.6 kmh) the engine is at 3330 rpm. 230 SL likes high revs, because it has the max. torque (20 mkg / 196 Nm) at 4200 rpm, and max. power (150 HP DIN) at 5500 rpm. It works well at low revs (advantages of the injection system), but when the sound of the engine seems to ask for another gear (around 4000 rpm), the best of it is still to come! It sounds even better at 4400-4600 than at 3500 rpm, and with better gas pedal feeling too.
It has a really short transmision, because max.speed of 200 kmh (124 mph) is at 6370 rpm, 870 rpm over the max.power! But if your cruising speed is not very high (as 65 mph), the advantage is that you have a final gear with good gas response. And be quiet, at such speed of 65mph and 3300 revs, it works in a very relaxed way, just caressing the gas pedal (Last year I did a travel of 1150 km -714 miles- in one stage, at around 110-120 kmh (68-74 mph) of cruising speed, very comfortable and with very low fuel consumption)
About the literature, you can buy from the Mercedes-Benz Classic Center in Fellbach (Germany) the famous Service Manual BBB (Big Blue Book) for the 230 SL and 250 SL, but it's only in German (Ref. 6510 1402 00, 68 euros, 888 pages). There's the same in English for the 280 SL (6510 1404 02, 73 euros, 1076 pages). There's also the complete Spare parts list for the 230 SL (6510 4431 41, 53 euros, in German/English/French), and the Spare parts list (without engine parts) in stock and with current prices from MB, for all W113 (6510 0000 04, 17 euros). For more information, you could ask in: classic.literatur@daimlerchrysler.com
Best regards,
Albert de la Torre Chavalera
Barcelona (Catalunya/Spain)
Feb.'64 230 SL Euro 113042-10-002432