I am placing the info I have. You may or may not already be familiar with this:
398th Engineer Regiment
Mr. Joe Ciampa
(806) 233-5276
This is all I have at the moment, but I will continue looking.
Have you tried contacting NARA in Maryland? They have different records that St Louis does not, such as after-action reports and all the reports from S-1 through S-4. That includes daily, weekly and monthly reports from the units. It is worth checking out. This is where I received over 2000 pages on my dad's unit. I cannot promise you that you will find as much, but you never know what you will stumble upon. So if you want extensive history, please look there.
I have all the contact information listed in the Research section of this forum. Please let me know if you have any questions.
Best of luck to you,
M
Proud Daughter of Walter (Monday) Poniedzialek
540th Engineer Combat Regiment, 2833rd Bn, H&S Co, 4th Platoon
There's "No Bridge Too Far"