what year 560 sel would i need and will it wire up the same as my 420 4.2 motor now? will i need my fuel injection? every thing still works on my car but the overhead cam motors aren't my specialty and i could only find one head gasket listed at some of the local parts stores where i live which was kind of deterring me from replacing the heads off of one i found(the only one in this area) in the wrecking yard,not knowing what shape the motor in that one is in, not running.I'm not opposed to keeping it all german if i can get the hp and torque up a lot more than it is now, top end has never been an issue but i've always ran big block chevy's in my hot rod so it's hard to compare a small block but i would like the extra put you in the back of your seat feel!! Thanks again.