I wouldn't waste my time with a 6.0. It's a great engine, but, the 8.1 is the cat's nuts for towing. Very reliable, too. Does not come with the Allison in the 2500 Suburbans or Avalanches, only the 4L80E.
My daily driver and tow vehicle is my 01 GMC Sierra 2500HD, 8.1L, Allison, 4x4, regular cab. Have had it for 8.5 years. Just turned 196k this past Monday. Bought it with 40k.
My Javelin is in pieces as I slowly restore her.
Ed, get 3m two part epoxy. Last four of that part number, 8101. Also, that is a spigot mount carb, so, a Raptor 350 carb may work. I had that 96 Wolverine with the BTM, and it was never a problem.
Well... The head doesn't have to come off. You could pressurize the cylinder to hold the valves closed. Of course, you'd need a special tool to compress the springs to break them down. And, there is almost no room to work with the engine in the frame, but, it can be done. Leaking valve...
What does it say on that cam??? It looks aftermarket. Which would explain the broken valve springs if someone didn't install better springs to handle the cam. Does not look stock that's for sure.