Crazy custom exhaust work suggestions

[LT1 Kayker]

I just gutted my cat and i have 2 1/2 inch piping into dual 3 inch tips. I found a new back end of an exhaust (the dual exhaust after the Y pipe) and its longer and is wider (4 inch compared to 2 1/2) than what is on my truck right now. The tips are 4 inch too. My truck is single piping after the downpipe and goes into dual 3 inch tips. Im just wondering what i would have to do to get these tips/exhaust parts on. I need to find a new Y pipe that has a single 2 1/2 piping into dual 4 inch piping. is that possible to even find? Any suggestions of doing this? I was thinking i could cut however much off of the new tips so i could get the right length, but i would still need a new Y pipe. Damn im confuzing...haha. Basically im wondering how my truck would sound with a gutted cat, magna-flo muffler , then after the muffler a Y pipe from 2 1/2 inch into dual 4 inch going into straight back 4 inch tips. Its kind of hard to explain what im trying to say but i think you can figure it out enough ill post pics soon. Oh yeah and i have a 305 carb engine. it sounds good with the gutted cat, but i need new tips and am wondering if i get these ones and do this it will make it sound deeper or better maybe. any help plz!