Reply to "Original yellow?"

OK. I'll start with the rear frame rail weakness at the A-arm attachment point. To do this, I will quote from Mike Drew's comments to the e-mail forum back on March 13, 2002:

Hi guys,

I had a fantastic time hanging out in Michigan Ohio with Gary Roys and other
club members and forum dudes Bob Timma, John Christian and Kirk Evans.

The primary purpose for the trip was to travel to Kirk Evans' shop, do some
destructive testing on early and late Pantera chassis rails and determine
once and for all if there is a significant design problem. While there is
plenty of anecdotal evidence supporting the contention that late-model
chassis is dramatically under-engineered, particularly in the rear lower
control arm mounts (recall that several of us have experienced separation of
the a-arm mounts from the chassis, most notably Charlie McCall), some owners
of later cars are especially sensitive to the criticisms heaped upon these
cars by the Pantera vendors who work on them every day. They cite an overall
improvement in development, comfort, and build quality and have big problems
with people levelling accusations of structural inferiority upon their cars
without any proof.

Well, here is your proof.

Gary Roys' GT5-S (recently sold) was up on jackstands in Kirk's shop, minus
any suspension, so it was a simple matter to bust out the Tool of Justice and
ziz some sheetmetal away to peer inside and see what is going on. Kirk
happened to have a pair of 1971 chassis frame rails literally lying around
which provided an excellent side-by-side comparison.

A peek inside the absolutely rust-free GT5-S chassis was somewhat horrifying.
Kirk has spent more time than just about anybody dismantling and
reassembling early Pantera chassis, but I believe that he hasn't really done
too much with the late cars other than import them and sell them. He
expressed considerable surprise at the comparative lack of spot welds on the
chassis rail, and the hokey tack welds used to join the two halves together
at the bottom. Upon opening the rail up, there was no visible reinforcement
except the tube, which he was able to move around by hand. He agreed that
this was grossly inadequate for the task at hand.

A comparison with the 1971 chassis rail showed that somebody was on the ball
back then--a second layer of sheet metal encompasses the inside of the frame
rail and has a good 20 or so spot welds to keep it in place. Inside the
frame rail is an extremely complex reinforcement structure formed from sheet
metal bent into an M shape and placed on end.

Bottom line--in this area, early cars strong, late cars weak to the point of
being dangerous. If he hasn't already done so, I'll let Kirk provide a more
expert design analysis, comparison and contrast. He told me he plans to
engineer a simple bolt-on or weld-on sheetmetal cover (similar to that used
on the early cars) which he will sell at cost to any owner of a post-Ford
Pantera.

One side note--both structures feature internal reinforcement of one type or
another that would be virtually impossible to deform simply by
over-tightening the nuts which secure the yokes to the chassis rails. There
has long been speculation that the several failures reported on the GT5-era ca
rs were caused by over-tightening, but that no longer seems to be a valid
theory.

Detailed photos and further analysis at

http://members.aol.com/panterachassisrails.jpg

Thanks to Kirk and Gary for helping settle this issue and hopefully solving
this potentially dangerous problem!

Mike

The above link no longer works, so if you want photos to go along with Mike's comments, I can e-mail them to you. The simple fix on my car was to use the side mounting plate of my lower rear chassis brace as a giant washer/frame rail reinforcement to distribute the loads from the two lower A-arm bolts. Mine was a custom brace, so before you buy a chassis reinforcement kit from a vendor you should ensure that it will work the same as mine.