Oldsmobile V-8 Engines. Bill Trovato
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The chart below is a reasonably accurate guide for people who have no means of properly measuring their clearances prior to assembly. The housing bore dimensions and the main bearing cap material both slightly affect the bearing dimensions. My experience is that the dimensions in these charts are within a few ten thousandths of an inch, and that amount is nothing to worry about. For those who feel they need to have bearing clearances within .0001 inch, simply measure your components. This data is for all for standard-size bearings; for use with undersized bearings, simply subtract that undersize dimension (.010 inch, .020 inch, .030 inch, etc.)
Small-Block Olds
Mains
| Main housing bore | 2.6870 inches |
| Uncoated bearing | Clevite MS805P |
| Dimension of bearing torqued in main housing bore | 2.5023 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.5000 | .0023 |
| 2.4995 | .0027 |
| 2.4990 | .0033 |
| 2.4985 | .0037 |
| 2.4980 | .0043 |
| 2.4975 | .0047 |
| 2.4970 | .0053 |
Mains
| Main housing bore | 2.6870 inches |
| Polydyne coated bearing | Clevite MS805P |
| Dimension of bearing torqued in main housing bore | 2.5010 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.5000 | .0010 |
| 2.4995 | .0015 |
| 2.4990 | .0020 |
| 2.4985 | .0025 |
| 2.4980 | .0030 |
| 2.4975 | .0035 |
| 2.4970 | .0040 |
| 2.4965 | .0045 |
| 2.4960 | .0050 |
Connecting Rod
| Rod housing bore | 2.250 inches |
| Uncoated bearing | Clevite CB684P |
| Dimension of bearing torqued in rod housing bore | 2.1273 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.1250 | .0023 |
| 2.1245 | .0028 |
| 2.1240 | .0033 |
| 2.1235 | .0038 |
| 2.1230 | .0043 |
| 2.1225 | .0048 |
| 2.1220 | .0053 |
Connecting Rod
| Rod housing bore | 2.250 inches |
| Polydyne coated bearing | Clevite CB684P |
| Dimension of bearing torqued in main housing bore | 2.1260 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.1250 | .0010 |
| 2.1245 | .0015 |
| 2.1240 | .0020 |
| 2.1235 | .0025 |
| 2.1230 | .0030 |
| 2.1225 | .0035 |
| 2.1220 | .0040 |
| 2.1216 | .0045 |
| 2.1210 | .0050 |
| 2.1205 | .0055 |
Big-Block Olds
Mains
| Main housing bore | 3.1890 inches |
| Uncoated bearing | Clevite MS804P and H |
| Dimension of bearing torqued in main housing bore | 3.0023 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 3.0000 | .0023 |
| 2.9995 | .0027 |
| 2.9990 | .0033 |
| 2.9985 | .0037 |
| 2.9980 | .0043 |
| 2.9975 | .0047 |
| 2.9970 | .0053 |
Mains
| Main housing bore | 3.1890 inches |
| Polydyne coated bearing | Clevite MS804P and H |
| Dimension of bearing torqued in main housing bore | 3.0010 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 3.0000 | .0010 |
| 2.9995 | .0015 |
| 2.9990 | .0020 |
| 2.9985 | .0025 |
| 2.9980 | .0030 |
| 2.9975 | .0035 |
| 2.9970 | .0040 |
| 2.9965 | .0045 |
| 2.9960 | .0050 |
Connecting Rod
| Rod housing bore | 2.6250 inches |
| Uncoated bearing | Clevite CB542P and H |
| Dimension of bearing torqued in rod housing bore | 2.5023 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.5000 | .0023 |
| 2.4995 | .0028 |
| 2.4990 | .0033 |
| 2.4985 | .0038 |
| 2.4980 | .0043 |
| 2.4975 | .0048 |
| 2.4970 | .0053 |
Connecting rod
| Rod housing bore | 2.6250 inches |
| Polydyne coated bearing | Clevite CB542P and H |
| Dimension of bearing torqued in rod housing bore | 2.5010 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.5000 | .0010 |
| 2.4995 | .0015 |
| 2.4990 | .0020 |
| 2.4985 | .0025 |
| 2.4980 | .0030 |
| 2.4975 | .0035 |
| 2.4970 | .0040 |
| 2.4965 | .0045 |
| 2.4960 | .0050 |
| 2.4955 | .0055 |
Small-Block Chevrolet
Connecting Rod (stroker applications)
| Rod housing bore | 2.2250 inches |
| Uncoated bearing | Clevite CB663 H |
| Dimension of bearing torqued in rod housing bore | 2.1023 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.1000 | .0023 |
| 2.0995 | .0028 |
| 2.0990 | .0033 |
| 2.0985 | .0038 |
| 2.0980 | .0043 |
| 2.0975 | .0048 |
| 2.0970 | .0053 |
Connecting Rod (stroker applications)
| Rod housing bore | 2.2250 inches |
| Polydyne coated bearing | Clevite CB663H |
| Dimension of bearing torqued in rod housing bore | 2.1010 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.1000 | .0010 |
| 2.0995 | .0015 |
| 2.0990 | .0020 |
| 2.0985 | .0025 |
| 2.0980 | .0030 |
| 2.0975 | .0035 |
| 2.0970 | .0040 |
| 2.0965 | .0045 |
| 2.0960 | .0050 |
| 2.0955 | .0055 |
Connecting Rod (stroker applications)
| Rod housing bore | 2.1250 inches |
| Uncoated bearing | Clevite CB745 H |
| Dimension of bearing torqued in rod housing bore | 2.0023 inches |
| Crankshaft Main Journal | Main Bearing |
| Dimension (inches) | Clearance (inch) |
| 2.0000 | .0023 |
| 1.9995 | .0028 |
| 1.9990 | .0033 |
| 1.9985 | .0038 |
| 1.9980 | .0043 |
| 1.9975 | .0048 |
| 1.9970 | .0053 |
Connecting Rod (stroker applications)
| Rod housing bore | 2.1250 inches |
| Polydyne |