I remember my older brother telling me when he worked at a Chevy dealership service department,one of his co-workers had to replace an engine in a later 70's G-10 van..which required removing the grille,radiator,hood and disconnecting all the various hoses and lines--not much different than a pickup truck--except for the fact in a van,the access SUCKS and you cant get at half the bolts from under the hood or thru the doghouse..it takes much longer than pulling a pickup's engine--but the flat rate book only allowed about the same amount of time to do it..
The mechanic looked over the job and said f***k that,I'm not doing it "their way"...instead he put the van on jack stands just behind the doors and removed the front suspension cross member (cradle),and took off the front brake lines and P/S hoses and A/C hoses,battery cables,radiator hoses,etc,and rolled the entire assembly,engine ,transmission and cross member,like a wheelbarrow on its front tires using a floor jack..
He then pulled the engine off the transmission,swapped all the external accessories to the new engine ,and put it all back together..it took him about 3-1/2 hours...other vans that had been done using the method GM detailed took a whole day,if not a day and a half..
Then the service manager said since it only took "half a day",that was all he was going to pay him for..