They just put a pair on an SR1 with modded 454's a few weeks ago.
Curious - the SEI drives are all Alpha replacements. I didn't think anyone recommended putting an Alpha behind a big block, especially a modified one?
I think SEI has been shipping their Bravo I lower replacements for a while now.
http://www.sterndrive.cc/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=121LU