Head casting numbers and the head casting date are located under the valve covers, in the rocker arm valley.
| Casting Number | Year | Valves | HP | Chamber | Notes |
|---|---|---|---|---|---|
| 10088113 | 86 and up | 1.94/1.50 | N/A | 57cc | Late model aluminum Vette heads. |
| 12558062 | 97 and up | 1.94/1.50 | N/A | 76cc | L-31 Vortec castings. |
| 14096217 | 90 and up | 1.94/1.50 | 300 | 64 CC | Heavy duty casting. Small plug. GM crate 350 heads. |
| 333882 | 70-80 | 1.94/1.50 | 150-180 HP | 76 CC | Intake flow 137.2 CFM Exhaust flow 95.4 CFM These are crack prone! |
| 340292 | 73-80 | 2.02/1.60 | 300HP and up | 64cc . | High performance heads. hard to find. angle plugs. |
| 3782461 | 61-70 | 1.94/1.50 and 2.02/1.6 | 250-375 | 64 CC | No bolt holes These are the double humps. |
| 3890462 | 62-68 | 1.94/1.50 and 2.02/1.6 | 250-350 | 64 CC | No bolt holes These are also double humps. |
| 3917291 | 62-69 | 1.94/1.50 and 2.02/1.6 | 275-350 | 64 CC | No bolt holes These are doubble hump heads. |
| 3917292 | 67-68 | 2.02/1.60 | 350HP | 64 CC | Corvette heads. |
| 3927186 | 68-72 | 1.94/1.50 and 2.02/1.6 | 290-370 | 64 CC | has bolt holes These are the doubble humps as well. |
| 3932441 | 67-79 | 1.94/1.50 | 250 and 255 | 76 CC | Intake flow 152 CFM Exhaust flow 93.2 CFM These have flat seat spark plugs. |
| 3947040 | 68-70 | 1.94/1.50 and 2.02/1.6 | 290-370 | 64 CC | |
| 3947041 | 68-70 | 1.94/1.50 and 2.02/1.6 | 290-370 | 64 CC | |
| 3973414 | 64-70 | 2.02/1.6 | 360 and 370 | 64 CC | Z-28 and Corvette LT-1. |
| 3973487 | 68-79 | 1.94/1.50 and 2.02/1.6 | 165-330 | 76 CC | X casting has 10 more intake cc volume. |
| 3998993 | 68-79 | 1.72/1.50 and 1.94/1.50 | 115-175 | 76 CC | Intake flow 150.8 CFM Exhaust flow 91.1 CFM Heavy duty casting. Small plug. |
| 462624 | 76-87 | 1.94/1.50 and 2.02/1.60 | Not listed | 76 CC | These are crack prone! |
| Casting Number | Year | Valves | HP | Chamber | Notes |
Another reference page Year One GM Engine ID