[Simh] VAX simulation

[Tim Newsham]

I'm interested in playing with some of the older VAX distributions
(32V, 4.1BSD, etc.).  I was wondering if it is possible to
configure Simh's VAX emulator to look like a more traditional
VAX.  The vaxmod_defs.h file says the configuration is based on
"the KA65x ("Mayfair") series of CVAX-based Qbus systems."

Is it possible to configure the system from a simh configuration
file to be more like an 11/750 or 11/780?  Has anyone done this,
and if so, do they have a configuration file?

Is it possible to adjust vaxmod_defs.h to make a more 11/750 or
11/780-like system without otherwise changing the vax simulator?

Are the differences between the newer and older systems significant
enough that the simulator itself would need to be hacked significantly?

Finally, are there any online resources that describe a typical
setup of an older machine in enough detail to achieve any of
the above?  What are the major differences between the mayfair
and the older machines (io addresses?  roms?  cpu differences?)?

Tim N.