I changed my 1680 over to the long sieve system a few years ago. We put the 2188 braces on two years ago because the rails were cracking out. It wasn't hard to do. Worst part was filing corners of a hole to make a carraige bolt fit.
The cast supports are a replacement for the steel channel ones. Should not be too much of a job to install. Biggest thing here is to make sure that the shoe is square in the machine and the hex shaft is square going thru as well. Quick check for this is with the belt off the drive pulley on the right side of the machine you should be able to rotate the shoe thru a complete cycle without any binding.
I was considering putting a long shoe in my 1680 but was told the frame was not the same and that it wasn't feasable to change it over. I didn't bother looking into it after that. Please tell me what you had to do and how much trouble it wasIJ Are you satisfied with the longer shoeIJ Would you do it againIJ Thanks, Dave
Boy There are options out there the two best ones are to weld in a support plate under the hanger and weld a angle iron onto it to bolt the old bracket to or the other option is to put in the cast bow ties from a 2388 . PS i have a couple sets of bracket from the updates we did at work that are no longer useful for the 2388 owners.They are all in excellent condition. I did about 10 of these jobs in the dealership that i work at .