so i have a garrett t3 t4 turbo and it went bad and i got a new one but the new one has a 4 bolt down pipe and my other one is 5 bolt down pipe. but both are .63 on the exhaust side and .60 on the cool side. so i was wondering if it is interchangeable bymyself or do i need to take it to professional?

 

If its the standard 50,57,60 trim series with the the stage III wheel (2.559" wheel diameter on the turbine side), then it is possible as long as the other housing is the same. But remember this, newer ones are almost $200. You can try and find a used one, but many people are not separating turbocharger components. Best bet is to cut that flange and have a 4 bolt weld flange ($23) welded instead.

 

Well he already has them both. To take off the housings just un bolt the backside of the turbo there should be like six bolts. Take them all out and the housings should just slide off.