no you cannot. Or at least, it would take 2-3 times as long and require a huge amount of stuff to be removed to do it "in the engine bay".
To OP....it's probably not worth bothering doing the sorts of changes people are talking about in this thread, unless you are pulling the motor out. And if you are, you may as well do new bearings ($300) + forged pistons and rings ($1000) as well.
I would suggest just run it, and be prepared to rebuild if it fails. Even better, buy a second long motor and start building it properly, and sling it in if/when the other one fails. A second hand rb26 long motor shold be about 1500-2000.