Dogs seem to be so more resilient than us humans eh! Glad all were ok.
I’d be learry of putting that combo in there. The 404 doesn’t have engine mounts. The weight of the engine is on the tranny housing.If there's room in there, a Cummins 6Bt and ZF5-42 would work well. I designed a conversion plate to mate the ZF5-42 to a Land Rover LT230 full time 4x4 transfercase (which was then copied and marketed by a Reece Myers in the UK), which i fitted into my Land Rover 101. It was a perfect engine, with good road manners, plenty of power and sensible speed. By making the plate, I was able to keep the transfer case close as the wheelbase of the 101 was short (101")!