How can you tell an SC engine from a 2.7 ?
 

When looking at a 911 at an auction and you have no details but a visual inspection of the car how can you confirm that the engine in a 74 has been replaced with a 3.0 L. Is a red sroud a reliable indicator. There are many listings for 2.7 engine numbers but I can't find any for 3.0 L engines ?

John, I'm pretty sure SC is when Aluminium crankcases returned. These cases are generally brighter than the dark grey magnesium of the 2.7

Anybody else?

emcon5, legend ! Thank you Very much ! You just answered all my questions thanks!

Actually all but one ... I know where the engine number is stamped on the engine but where is the engine type stamped ?

Look at the floor under the rear of the car. The 2.7's will generally leak more...
(I'm ducking for cover!),
-Chris

And, I might add, they..... last!

Rt side near fan-just under oil pressure sender

If it actually running you could probably come up with a statistical method for determining if it is a 2.7 or a 3.0 weighing in area of the oilspot, smoke volume from exhaust, # of head studs rattling, year of car it is in,.......etc. Or you could look to see what the case is made of.:D