I recently swapped my 305 for a 400sb in my 85 camaro. I bought a set of headers at a swap meet, and I'm having issues with the front tube on each side hitting the top of the engine mounts on the engine. Could I just grind or cut the top corner off the engine mounts, or do I have to get new headers? I really dont want to put the manifolds back on it, nor do I want to crack a mount...

 

Are the headers you got specifically for thirdgens? If not then they probably wont work. But if the only part hitting is the front tube you may be able to dent the header for clearance.