I think you're being a little harsh, John.
Certainly the auto trans is going to suck up some power, but Chevy used the 700-R4 behind the 173 ci v-6 in the S-10 and the Camaro.
If Marcel has a 250, I think a v8 700-R4 will bolt up. He'll need to buy/fabricate a rear support and a driveshaft. He might be able to adapt the column shift or replace it with a column from an auto car. Or use an aftermarket floor shift.
Like you said, a large effort. Probably even more so in the Netherlands. I'd be reluctant unless there is some reason to delete the manual. An easier way to get overdrive is with a manual trans replacement to the Saginaw or Borg Warner 3 speed OD trans.
regards,
Leon
