Can you make a 1971 g-body frame fit a 1972 a-body conv?
I've heard that you just need to shorten the frame by about 4", but I don't know
for sure and where to cut it. Plans/diagrams would be sweet.
The two were related but not necessarily interchangable. The 71 G body was used on Grand Prix (118 wb) and Monte Carlo (116 wb) The 72 A body (68-72) was 112 wb on 2 door cars and 116 on 4 door and wagons. So depending on your body style, you might make it fit. In addition, convertibles had a stronger chassis, so if you found something to fit, you might need to reinforce the frame.
Will my 1976 Grand Prix rear end fit on a 1970 Buick Riviera