will it fit?

Jim, It will bolt up but there are a few thing you have to do to make it work. One of the first is to obtain the tranny crossmember for the hydromatic. It is going to take a bit of modifying to get the hydromatic crossmember onto the spot where the standard tranny crossmember was. It will be a cutting job followed by a hole boring job. Also, you will need to change the driveshaft cushon system. Just unbolt the one from the 53 setup and put it onto the 54 setup. Also check your rearend ratios to make sure you have the best ratio rearend for the hydromatic. Normally they came with a 3.07 rear . Three speed jobs usually didn't. Don't need to get your 54 rearend screaming at 58mph. so check and make sure. The columns will interchange but you will need to hookup the neutral safety switch. 3 speed jobs didn't have those. Get one. It's important. Ought to be on the hydromatic 53's column. If you do have all the linkage then you should be OK. Oh ,make sure to check the condition of your motor/tranny mounts when you switch engines. Good time to head off trouble.Good luck on your engine job.