Bonjour Claude,
The forum is back up and I was looking around and found your postings. My name is Hudson and I am over here in Ontario also building a slabside form Chuck's drawings.
You can find my build posted as Canuck 289 scratch build. I am also using a T-5 and the 8.8 IRS rear. It is very possible but a couple of modifications were needed. Have a look and let me know if you need to know more details. I will be posting a long over due update very soon.