I went with the ATI case as well.
The best thing I ever did on my car is dump the CSR case and get an sfi case. ATI in my case. I'll never look back again. The sfi case is a hit on the wallet but it more than pays for itself in trouble free transmission r&r's. I picked mine up through FTI in Florida. Great customer service.
I have a question for all three of you, (as well as for anyone else who has opted for the SFI trans cases) that I'm hoping you will answer: Did any of you have to modify, cut, or grind any parts of the firewall, floor board, or trans floor tunnel on your Chevelles for clearance of the SFI trans cases you bought? I'd just like to know what I'm in for. Thanks in advance.The BEST thing I ever did on my car is chunk the CSR shield and get an SFI transmission case. For a while I was pulling the transmission on almost a weekly basis for converter changes. That was miserable 2-3 hour experience every time fighting that stupid shield. That was even after drilling a hole in the firewall to access one bolt because there was no other way. With the SFI case it is back to a 30-45 minute (depending on how inspired I am) exercise to drop the trans. and I don’t even develop Tourette Syndrome anymore when I change the transmission.