1978 impala springs and rear end?

Would they fit?

Friend brought them to me and hate to see it go to the junkyard.

short answer yes

buickestate wrote:

short answer yes

Long answer? Lol, if ya care to tell me...

would need more details to give you the long answer. are we talking about a 78 wagon or sedan?

Sedan

is it a posi unit?

A sedan rear has a slightly different spacing for the mounting points. Also, it may be the weak 7.5" rear. Even if it is the 8.5", it will have the weaker 28 spline axles (your wagon has 30), and the outer axle bearing will be smaller than the wagon. So, not really worth swapping the whole thing in. Even if it is a posi, you can't swap that into your car because of the axle spline difference.

Sedan springs will be weak for a wagon.