GM A-Body IRS

[ProTouring442]

Since I have been working and reworking my '72 442 convertible for something like the last 15 years, I thought I might "upgrade" to IRS. Why not, right? I figure I will sell my Currie 9" to fund this little project.

So I figure I have six basic options.

1) C-3 Covette

pro: Uses the half-shaft as the upper control arm. This makes narrowing difficult, but it also alleviates the problem of upper control arm/frame interference.

con: The unit is difficult to adapt given the transverse spring, and trailing arms.

2) '69-'87 Jaguar

pro: Uses the half-shaft as the upper control arm. This makes narrowing difficult, but it also alleviates the problem of upper control arm/frame interference. Comes in an easily adaptable "cage." Center section is essentially a Dana 44. Readily available for little money.

con: Unknown axle strength. No trailing arm.

3) MN12 Thunderbird/Mark VIII

pro: Strong. Comes on a readily adaptable carrier.

con: It's 2" too wide. Not easily narrowable (cast lower control arms).

4) Mustang Cobra

pro: It's an inch or so narrower than the A-body rear. Comes on an easily adaptable carrier. Strong.

con: Known handling issues. Not cheap.

5) 200X GTO

pro: Easily adaptable. Inexpensive.

con: Strength (both the differential and the suspension components)?

6) Pontiac G-8

pro: Comes on an easily adaptable carrier.

con: Strength (both the differential and the suspension components)?

Remember, this is a bit of a Pro-Grand-Touring car; a backroad burner, long distance tourer, and not an autocross machine.

I was leaning toward the MN12, but after reading about the Jaguar unit, I think it might be a good choice. It even has the right wheel bolt pattern. I think the adaption of a trailing arm to the factory A-body might help with wheel hop?

Anyway, looking for thoughts and arguments regarding any of these.

Shiny Side Up!
Bill