Is it possible to change the main bearings in a small block Chevy with engine car?

Yes, it's possible to change the main bearings in a small-block Chevy engine in a car, but it's a very difficult and time-consuming job that requires significant mechanical skill and the right tools. It's generally considered a more advanced engine repair.

Here's why it's challenging:

* Accessibility: Working on the bottom end of an engine while it's still in the vehicle severely limits access. Many components need to be removed (oil pan, timing components, possibly even the transmission) just to get to the main bearing caps.

* Precision: Main bearing installation requires precision to ensure proper alignment and clearance. Improper installation can lead to catastrophic engine failure.

* Specialized Tools: You'll need specialized tools like a main bearing alignment tool, a torque wrench capable of accurately tightening the main bearing caps to specification, and possibly a crankshaft puller.

* Risk of Damage: There's a considerable risk of damaging the crankshaft, block, or other components during the process.

It's strongly recommended to remove the engine from the car before attempting a main bearing replacement. This significantly improves access and reduces the risk of damage. While doing it in the car *might* be possible for a very experienced mechanic, the extra difficulty and risk often outweigh the convenience of leaving the engine in place.

If you're not experienced with engine rebuilds, it's best to leave this job to a professional mechanic. The cost of a professional repair is far less than the cost of damaging your engine during a botched attempt.