* Original Rear End: A 1968 Nova could have come with several different rear end housings, varying in width, axle ratio, and even the type of differential (e.g., 8.2-inch, 8.5-inch, 10-bolt, 12-bolt). Identifying the original rear end in your specific Nova is the *first* step. Look for casting numbers on the differential housing.
* Housing Width: The width of the housing is critical. Different Nova models and trim levels might have used different widths to accommodate the body and wheelbase. A rear end from a different year Nova, or even a different GM car, might *look* like it fits, but the width might be wrong, causing axle shaft issues or misaligned wheels.
* Axle Ratio: This determines your car's gearing and affects performance. You'll want to choose a ratio appropriate for your intended use (highway cruising vs. drag racing).
* Differential Type: The type of differential (10-bolt, 12-bolt, Posi-traction, etc.) affects strength and performance capabilities. Again, this needs to match your application. A 12-bolt is stronger but heavier.
* Spring Perches: The location of the leaf spring perches on the housing must align with your car's chassis. A mismatched rear end will require significant modification (potentially welding) to work.
Compatible Rear Ends (General):
You'll find compatibility with other GM vehicles from the same era (late 1960s and early 1970s), but thorough research and potentially some fabrication are necessary. Some examples *might* include rear ends from:
* Other Chevy Novas: From the same general time period (late '60s and early '70s). This is the most straightforward swap, though you still need to match width and ratio.
* Chevelles: Sometimes compatible, but you need to carefully verify the housing width and spring perch locations.
* Camaros: Similar to Chevelles, verify all dimensions are correct.
* Other GM A-Body cars: These are often a good source of parts, but again, double-check the specifics.
Before making any swap:
1. Identify your original rear end: Find the casting numbers and look them up online to determine the specifics.
2. Measure your original rear end's width: This is essential for finding a compatible replacement.
3. Research thoroughly: Use online forums dedicated to classic Chevy Novas to get advice from experienced owners. They can help you determine the best rear end for your project.
In short, there's no simple answer. A professional mechanic specializing in classic cars would be a great resource to help you select and install the correct rear end for your 1968 Nova.
