Need help on replacing old caliper brakes!

[toker_ace]

I'm building a bike out of old parts laying around.I think I'm going to get me a jackshaft for the first time.My question is this bike has the old caliper brakes and they suck! Is there any way I can replace them with some other kind of brake that will go threw the hole like these brakes mount. Any help?

 

[fall_down_stand_up]

I went to my local bike shop and bought my shimano break caliper set for a total of 16.00 for front and back....It did wonders....Take the old ones off and take them into the bike shop and he will set you up with the ones you need....They work so smooth now,also make sure you grease the cable before putting them in the theathing,if the ends of your cables are frayed you will have to buy new cables and they ran me 3bucks a peice....
John-John