Dad was following too close behind a truck that lost an outside dual,when I was a kid. tire was still upright,when he ran over it,in a '52 Pontiac,(straight 8). Didn't damage the sheet metal,but wrecked the radiator,and both manifolds,plus cracked the block. He had a shop "stitch" the block,and the manifolds. Held-up for 10 years,until he junked the car. I've had real good luck with JB weld,too,as long as you grind the crack,like Jerry suggests. The key is the curing process. Apply a 100 watt bulb,(explosion-proof trouble light),to the repair,and let it set-up for at least 12 hours. We always allowed 24,just to be double safe. We repaired a dozen,(or so),using this method,and never had a customer return with a "repeat offender". just the normal tune-up,brakes,etc. hope this helps.
