Allante V8-273 4.5L (1991)
The bearings should be used only in engines with the structurally improved crankcase shown in Figure 2. For bearings to be used in the earlier crankcase
shown in Figure 1, refer to Service bulletin T-92-132.
Crankcase Identification:
To determine which style crankcase is being worked on and hence which bearing chart applies, refer to the figures. Note the 1991 model year vehicles
may contain either crankcase (as well as earlier model year vehicles that have experienced an engine replacement).
Structural changes have been incorporated in the transverse crankcase to keep up with steadily increasing power outputs. Figure 1 shows a "typical"
crankcase that shows the only significant differences for purposes of bearing selection. Earlier blocks may not exhibit all of the features shown. 1990
style blocks have:
^
Less extensive ribbing
^
A "thinner" pan rail
^
A letter identifier other than "Z"
The 1992 style block shown in Figure 2 has:
^
More ribbing
^
A thicker pan rail