I converted my Mirada to the early style. It's much easier to find gears. The adapter is metal not plastic so it seems more durable. The cable needs to be changed to an earlier version. I needed a longer one for my 518 transmission swap so it was a good time to make the change.
No, 1 1/2 x 1 1/2. A couple of installation tips: bolt the shocks on to locate the proper position, make sure the bolts can be removed, and check exhaust clearance.
My Mirada always made a strange boing sound when going over bumps. I couldn't find anything loose so I made a heavier version out of tubing since the crossmember seemed to be the flimsiest part in that area. I'm sure the shocks are more effective now and the sound is gone.
I had 3.23's in my daily driver Mirada and I thought it was the perfect ratio. When I installed the overdrive transmission I went with 3.91. Gear swaps are the best bang for the buck.
I should mention that it needs to be the later version. The earlier version doesn't have the odometer reset button going through the gauge face like the J-body.
Surprisingly an E-body speedometer bolts right in. I found an original but I think they're reproduced now. I also installed the matching tach but that requires some cutting and splicing of the circuit board.
I had a fuel line leak once. Just enough of a leak for the fuel pump to suck air but not enough for it to leak fuel. It was on top of the frame rail under the control arm.
I removed the flimsy shock crossmember and replaced it with a piece of mild steel tubing. I would absolutely recommend this modification. It eliminated a "boing" sound that used to come from the back of my car.
I tried Blackjack and Hedman, neither of which would fit. I went with 340 manifolds for years which require a smaller brake booster. Eventually I tried TTI which fit like a glove. I would definitely recommend them. I was even able to eliminate the oil filter adapter.
Once you get the proper distributor installed, you'll need a source for ported vacuum. If you're keeping your lean burn carburetor then this might be the hardest part of the job.