Im not saying its easy but I changed the whole top end of my engine while it was still in the truck last year.Are you going to scrape some knuckles heck yeah.What I did is I had my body raised with my jack and went through the fender wells to get the bolts i couldnt get from the top.By removing the engine you are doubling the amount of work you have to do.I didnt do this on my Blazer but I seen somebody else I know that had one take their front clip off which makes it alot easier.Maybe try doing this?