Clicking 3 L GTV-6 and 355 Differential

[gmcnp@domain.elided]

I've been thrown off all the gun lists for discussing Alfas, so I guess
I'll have to post my belated views on the issue of what final drive to
use in a 3 L GTV-6 on the AD.  My car currently has the 355 from the
Verde that died so my 6 could have a new lease on life.  I really like
the "seven league boots" that this higher final drive gives, compared to
my car before (not much of a comparison) and to the running '86 parts
car I bought last year from another member of the AD community.  First
gear is usable for fast exits from low speed corners (5 to 20 mph), and
freeway cruising is relaxed.  My car has no shortage of grunt either,
but has Colombo pattern cams, polished heads and intake runners and a
revised chip (using spark box and AFM from the Verde).

I recently ran the Car Test program for which someone posted a link on
the AD some time ago to compare the 410 and 355 rear ends.  I modified
the 2.5 L GTV-6 data entry by boosting HP and torque and made separate
entries for each rear end.  Surprisingly, the 355 was almost .5 seconds
quicker to 60 than the 410, in a statistical dead heat at the quarter
mile and within a few tenths everywhere else.  This is somewhat
artificial, since the 355 makes the slow 2 - 3 upshift at 65, whereas
the 410 shifts before reaching 60, and a similar effect between 3 and 4
must be occurring on the times for the quarter.  Nonetheless, if you
believe this program, the benefits of the change in terms of
acceleration are modest.  

Of course, one would have to drive cars with both set ups back to back
to be sure.  The 2.5s I have driven with the 410 are not really a fair
comparison, since the 3 L motor makes them seem slow even with the 355
rear end.  Doug S. has offered to let me drive his 410 equipped 3 L
GTV-6 (which he loves), but I never get down from upstate NY to try it. 
One of these days.  But until then, I am not counting the 3.55 out.

Now a question:  when I stand on the throttle above 4000 rpm (when the
big torque comes in), I get a loud clicking sound coming from under the
car that sounds like the noise you hear when pulling up a ratcheting
parking brake, except much louder and the sound will continue until I
get off the gas.  The same thing happens at even lower revs if the
pavement is wet.  I know it happens when the drive wheels spin, and it
may happen under strong acceleration even when I don't spin the rear
wheels.  Why would it make this noise?

George Pond
Black 3 L GTV-6
White Spider

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