what is involved in changing brakes from power to manual brakes? thanks.

What year, and model?

its a 69 r/t with 440 and disc setup off of a 73 a body.

Get a manuel disc master and correct pedal rod. Manuel brake cars don't use the pivot linkage. They also use a different plate behind the master.

thanks, that will get me going in the right direction.

I'd contact Ehrenberg or Dr diff to purchase the correct bore alum M/C so you will end up with the bore size that will give you the right pedal effort the 1st time which if off will get old real quick. As said a manual pedal push rod & maybe a MP adjustable length one. A manual brake M/C will have a wide groove inside the M/C piston cavity (The "thimble" so a piece of vac line on the end of the end of the pushrod) to retain it which is not needed on a PB setup.