The 250 rules! shorter stroke winds up quicker and higher = goes faster in less time!

But, if you want pulling power and low end torque stay with the 292. Look at it this way. Your 292 was specifically designed to work good under a load in pick-ups and bobtails. The 305 was designed to get decent milage while running poor quality regular gas with out knocking. that understood ask yourself what do you want your engine to do?
Boo