$400 to fix my 92 honda accord. the mechanic said it needs a new distrubutor ect....

...is this too expensive? my honda stalls as you are driving. i just want to know if this is reasonable, $400.00 no tax for the new distrubutor parts labor ect. ($120.00 for distributor) Please any advice would be helpful.
92 honda accord lx 166, 000 miles.