my 360 had a bad leak at the rear of the engine. I pulled the trans and flywheel. I found 2 big cracks on the back of the motor next to the freeze plug. I can weld cast,but should I even try. I dont want to get another block.

 

The block freeze without anti freeze?
Don't try to repair it, it's a gone.
Look for another block and build again
but go for a 390 or 410.

Hey welcome to the forum.

 

Welding the block isn't the problem. Getting the oil passage sealed up is going to be a problem. If you're going to try and save the block, tear it down first and see if there's any possibility that the oil passage can be sleeved or sealed.

As common as 360/390 blocks are, I think you'd be better off getting another block. And a 390 crank and rods... :-)