6.0, as previously stated...will get you your 13s no problem.

 

I would go 6.0 and not waist time on the 60e. I would take a stock 80e over any built 60e.

 

I know how strong the 80e is, had one in my other truck. On this one, I am not messing with an 80e swap. Found a few 6.0s, but found a bunch of very low mileage 5.3s for half the price and one of them is very tempting. Waiting to hear back on the 6.0s on how many miles some of them have.

 

If you are getting a 6.0 the 80e is a crossmemeber and a plug away. The 60 would probably be harder to mount to the 6.0. Now a 5.3 would be a differant story.

 

Well picked up my low mileage 5.3 today. came from a 2004 gmc. still trying to figure out what trans to use, waiting on contact from a couple builders still.