I'm looking at a parts bus purchase.  It's a 77, and it will be worth
more to me if it has a T4 engine WITH hydraulic lifters (late 77
model) than without (early 77 model).  I want to firm up my offer to
this guy, but the engine doesn't run and he's not sure which lifter
mechanism it has.

Is there some easy way to differentiate the two engines?  Does anyone
know the serial numbers/engine numbers of the last bus without
hydraulic lifters or the first bus with hydraulic lifters?

Please copy any responses to me directly in email at
<boleyn@scr.siemens.com>; I may be finalizing this buy very soon
(tonight or tomorrow).

This parts bus is to help me rebuild another bus I haven't bought
yet--a 78.  This 77 is to be my "practice" bus :-).  First purchase;
not very familiar them yet.

Thanks,
Rodney <boleyn@scr.siemens.com>

P.S.  Along the same lines, I've seen in RMMW catalog they list
different engine computers for California and non-CA buses of
the years 77, 78, and 79.  I.e., six different engine computers.
What are the real differences between these 6 ECUs?  Could the
ECU from a 77 be used on a 78 engine, would it run?  Would it
harm the engine in any way?  Or is it more a matter of subtle
things like acceleration profiles vs. emissions requirements?