Don't tell Mel, but I've been toying with the idea of putting a cummins engine (probably a 4bt) into my truck. I'd like to keep the ZF5 I have in there now. There are some commercial adapters out there, but many of the bread truck donor engines I've seen have adapters with them as well. What I can't quite figure out is what the deal is with the stock adapter between the 6.9 and the ford flywheel? Is the back of the IH engines an SAE pattern, or is it something else entirely? Thanks for any info!