The 2nd Gen R/E in a 1st Gen swap usually creates more problems than it is worth. The 1st Gen R/E's are 9/16-5/8" narrower on each side. This effects the placement of the outer section width of the rear tires. Ck your current tire/wheel combo & if you have any plans for future bigger tire & wheel combo's take this into consideration. Certain wheels are only available in certain offsets & wider axle to axle R/E can create a problem. 99% of '71-74 2nd Gen R/E's will have the small Spicer 1310 u-joint pinion flange & will have to be swapped over to the later 1330 flange to mate up to the stock 1st Gen bird driveshaft. Original driveshaft will also have to be shortened 1" to work with the bigger pinioned 8.5.
To get around the R/E width & perch prob's the proper width 8.5 X-body (Nova) multileaf R/E can be used to build with the '79-81 T/A disc parts & posi unit. By doing so one gets a R/E with the perches in the exact spot, correct pinion angle & in the exact width. Have built over 200 of these 8.5 "big ten" R/E's for 1st Gen cars, email for any specific questions.
