I’m very confused on what to do and sometimes I have troubles explaining things so sorry in advance guys! So I got my hands on a 85 fox body mustang. I don’t know much about the building world but it really interests me. It has the 5.0 GT motor and it’s a 5 speed manual. I don’t know much about it however it’s a carbureted one. I bought it off my uncle after he blew the trans. It has shortie headers and dual exhaust don’t know much else. When buying the transmission I didn’t do A LOT of research I just knew I wanted to achieve at least 500-600hp so I instantly went and searched for a transmission which could hold it. I ended up finding and buying the Tremec TKO 500. However I didn’t realize I would maybe have to swap out the rear end to match with that transmission. Like I said I don’t know a whole lot of the more in depth side of it. It fast but it seems like it tops out quick and doesn’t want to push further at a certain speed but it feels sluggish to me and seems like it’s reving high. The speed cable isn’t hooked up yet so I can’t tell which speed or rpm’s I’m at right at the moment.. so for the sound of the revs that it’s giving and the speed it’s possibly going it feels like there’s still a little more it could give on the top end and that’s where it feels sluggish. It has no problem getting up to speed which is fun. It just doesn’t feel like it’s giving the same amount of juice it sounds like it could while being at said rpm’s. it kicks sideways and will burn the tires from dead stop but only a light strip a few feet I like to see it a little darker so would even setting in a different rear end give it more power to the tires? The backs are 265 width with 17” rim but I just can’t remember the sidewall maybe 45 maybe 50 not at the car right now and its 11pm while raining. I want it fuel injected, and I don’t know what I want to do if to rebuild that one and convert it or just get another motor and swap. I’m very lost. Any help would be greatly appreciated if you guys can make since of my rambling on haha.. thanks!