71 440 rod and main bearing, advice needed..

Being as yours is a 71 block it should use the smaller thrust bearing diameter.
The info below is from 440 source.com

Clevite 77 Main Bearing Info.

Because "B" (361/383/400) and "RB" (413/426/440) engines use different size main journals, each will have a different size main bearing. The "RB" uses a 2.750" main journal diameter, while the "B" uses a 2.625" so the two sizes are specific to each engine, however there is one additional difference...

From the beginning of production (when these engines were designed) in 1958 up until the 1973 model year the diameter of the thrust surface's outer edge (on the #3 bearing) will be approximately 3.470" for the "B" engine and 3.600" for the "RB" engine. Starting in the 1974 model year, this diameter was increased approximately .280 thousandths to 3.750" for the "B" engine and 3.880" for the "RB" in order the give the thrust surface more surface area. To allow the new larger bearings to fit, the machined recess area in the block webbing and the main cap in which the thrust bearing shells fit was increased an equal amount.

In the picture below, we have put two #3 thrust bearing main caps together. The one on the bottom is from an early block, and the one on top is from a late block. You can see the difference in the size of the machined recess area.



We refer to the pre '74 bearings as "Early" and the 1974 and later as "Late." It is possible to use the early (smaller) #3 bearing in all blocks, regardless of the year manufactured. For this reason, we offer bearings with the "Early" style thrust flange only. Using the later style bearings in an early block is not possible since they will be too big to fit in the smaller machined recess area. All other bearings except the thrust (# 1, 2, 4 & 5) are the same for all years.