What he said in the above post. Also, from what I understand, the passenger side motor mount is in a different location from the 250 and the 292... The motor mount on the pass side of the 292 is in a more forward location compared to the 250. (at least, from everything I have seen, anyways)
292:
Note the pass side motor mount in front of the fuel pump and taller block... characterized by the taller pushrod gallery covers.
250:
Note the fuel pump location in front of the motor mount. Also this shows the difference in height of pushrod gallery covers. The 250 has shorter side covers.
The inline sixes are very reliable and will seemingly run forever. I had a 250 in a '66 chevy van that I drove for over 10 years. It was reliable, but not very powerful.
The 292 has a monster 4.120 inch stroke and that is why it makes a sh*tload of bottom end torque and can pull like an ox! The stroke on a 292 is bigger than that of a 454 or even a 502 BBC! The 292 is an awesome engine.