Andrew, That is a nice looking setup on the big block!

For the guys that are dealing with "drop out" and wanted to use what came with them
most can sell off their existing accessory drive to recoup some cash (granted the truck setup isn't in high demand, but will get some money back)
also, I look at it and explain to people that I am working with that, at this stage in the build prepping a drop out engine, cleaning, detailing, I recommend replacing anything that you can, while the engine is out and easily serviceable!

I always install new rear main seal for one and the water pumps are usually questionable, especially given the mileage/ usage, then being pullout out and these engines sit for some time
Why chance it with a used waterpump, it is less than $100 for "insurance",rather than firing the engine and finding out it leaks??

Jeff

Very good point Jeff. Sometimes we get in a hurry and don't think things through and the outcome of not replacing some small things that may or may not cause a problem after the engine or trans is in the car. Thanks again for some good advice.

you are welcome!

That is why we are all here! To help each other out and give helpful advice

It has happened personally to me with a customer that brought a vehicle in for a engine swap (LQ9 6.0L)
It was their supplied engine and I said that I would install a new rear main prior to putting in their vehicle, he swore that he trusted the engine and didn't want to spend the additional $15-20 for the GM seal ??
I advised that he should do it and it would cost more time and money to change it later
I guess being in Las Vegas, he took a gamble!!

Well you can guess the outcome, initial startup engine was fine, drove around block, came back to a small trail of oil coming from where?? rear main!!

had to charge him to pull trans and install a new rear main seal!
Let's just say that it cost alot more than the $20 for the seal!!!

Jeff