Re: Need Advice... Real Bad-like

[david crooks <david.crooks@xxxxxxxxxxxx>]

Hi Todd,

As has been mentioned, the problem you've run into is that
AMC changed Auto tranny designs in '72.  Earlier used a
Borg Warner, and later used Chryco.  Unfortunately, the
back end of the crank is different for each...

To overcome this, there are two types of adapters on the
market.  The first, designed by AMC, requires machining
of the crank, making switching back impossible, not a
good idea in your case, when you want to return the 360
to the Machine!  The second version came out later, and
does not require machining of the crank.  Talk to the AMC
vendors for price, they'll know what you're talking about!

As for balancing, there's two way's of doing this as well!
The first, and best type, involves tearing down the engine.
The Pistons are weighed and matched, the Rods are weighed
and matched, then weights, based on the pistons and rods,
are attached to the crank, and the crank/damper/flywheel
are balanced.  That's the best way, but obviously it's
more work!  Next best is to match components, often referred
to as match balancing.  In this case, you'd take in two
flexplates, and ask the shop to make the new one match
the old one.  In your case, where you're planing on putting
the motor back in the Machine, match balancing makes the
most sense.

I don't like suggesting you spend money needlessly, but
I have seen emails from respected AMC people, like Tony
Zamisch, stating he's seen differences in early/late 360
flywheel counter weights, and balancing is a problem I've
personally hit, with my '70 390 (that I bought and later
discovered had a 258 I-6 Flywheel!)  I'd hate to have you
shake the bearings out of your newly rebuilt 360, while
running it in a temporary body....

Cheers, and good luck!

Dave