I once owned a 1988 Chevy pickup with a 305. It had quite a loud manifold leak and I discovered that the exhaust manifold was cracked directly below where the hose attached to the heat stove. I removed the manifold and the heat stove and found that it was nearly broken into two pieces. The crack was literally an eighth inch wide on one side. Because the manifold didnt have much holding it together, I clamped it to the steel bench and arc welded it with nickel rod. It didnt look very good because I didnt want to try and grind it before welding as I was afraid it would break into two pieces. After welding I ground it down a bit to get the real awful lumps off and then put several passes over the weld with the mig welder. It was on my truck for years after and never had a problem with it.

Paul

You're not thinking of welding your tubes are you Mark?

Either way I guess you need to get it straightened then if it's had a tube replaced so you could weld them.