I did a engine removal on a H80XL with the GM V-6 & it was a very tight installation. It took closer to 12 hrs for the R & R of the engine alone. It was not an easy job by any means. Good luck!

Thanks guys. I know it was very general. It is a fairly clean unit at a small sawmill, run on pavement. I wanted to see what differences in answers would come back. The engine is a 4.3L GM and yes, I would elect to bring it to the shop for the job.

I would agree with Ed t that variables can greatly affect this type of job. Without seeing the unit I would guess 8 hours but again- that's an estimate without seeing it.

That is like asking "can i ride a bike'.
It takes a bit more information to make this answer accurate.
I could 'shorthand', and answer with another question: "how long does it take you to pull the engine out and put it back, then add time for removing the flywheel and replacing the ring gear and putting the flywheel back on".
We would need at the very least a serial number, type of power-plant (Mazda? GM?) and if you are equipped and have experience to pull motors from a forklift. and then we would need to know the condition of the forklift. Some experienced folks may be able to do this inside an 8 hour day, but if the truck came out of a concrete plant, rendering plant or salt factory and had to have stuff chipped off all the nuts and bolts before they would turn, it may add considerable time to this job.