Transmission not shifting into second fully

Hello, so as you may have heard, I finallly got the baracuda back on the road. however, it seems to have developed a transmission issue (727). I put the car all back together, drove it a little and it's shifted through all three gears. I even took it on an 8 mile drive down the freeway. (got lots of looks too) When getting it back we readjusted the timing and dropped one of the clips on the trans, so I stupidly took off the linkage to get at it.
I put it all back together, drove it, it stilll shifted through all three gears. Then when my dad was in the car we went to the neighbor who originally sold me the engine. I drove past, saw him and backed up about 60 feet and up his driveway. I turned it off and then let it sit. When we started it up to leave it was very hard to get into gear to where my dad had to really haul on the lever to get it to move. After that it won't shift into second. It'll rev up, shift to second but the clutch doesn't feel like it lets go and drags the rpm down to where it goes back in 1st. It also has a worrying clunk/crunch when going into reverse. My dad looked at it, and adjusted the linkage to the lever but it still does it. It only has about 3000 miles on it, maybe not even. I wanna drive this car sooo bad, can someone help?