I'm running a 327 Chevy with a TH400 Tranny. I noticed that the TH400 has a 4.9" output shaft, and the u-joint bolts directly to the shaft. Since I am going to use a straight driveshaft (no center carrier), it looks as though I'm not going to have enough u-joint coupling shaft length for it to slide in/out when the rear end moves up/down. I know that when you measure for a driveshaft length, you have to pull the u-joint out 1"-1 1/2" for play.

Is this a safe thing to do on this tranny?

Should I change to a TH350 with a longer output shaft, from a car?

If I do, will the torque converter from the TH400 fit the TH350?