So I'm stumped. I recently did a 13b swap in I'm 82 (the 12a blew) I put in an 88 na with tranny into mine. I kept the car carb'd and went with an edelbrock (560cfm if I remember correct) took out ps and ac and street ported it. After I finished I drove the car for two days (took it very slow to break in) before I decided to swap my rear end. I read on some forums that my old rear was not the best and a local rx7 guy suggested an 85 rear end or a KIA Sorrento 4x4. I found an 85 rear and got it installed in a day. Didn't mess with any of the gearing of it. Once I got the car broke in I decide to see what I had. To say the least it was a let down. When I went I started in 2nd at about 2000 rpm and when I hit 4 the car like stalled. It felt like power was there but it wasn't getting to the wheels. I've done some looking and I've seen that with most carb upgrades you need to upgrade the fuel pump (still have stock) and I also have a weird vibration in the rear of the car when I start off in first and it last only til I hit around 10mph. So could it be something to do with the rear? I haven't had much time to dig into this with work. If anyone knows what I could do to get the car to preform like I know it should or where I should start looking it would be greatly appreciated.