Alternative to block off plate

[BlackLT1Z28]

While I had my manifold off, I blocked off the EGR ports in the back. But I can't get the block off plate on the header. Its the pacesetter's LT's. Anyways, its already in the car, and I was trying to slide the plate in, but there is no clearance for it. So, I'm kind of stuck. Do you guys know of anything that I could use to block that hole and take the temp of the exhaust? I don't want to have the exhaust leak anymore and I don't want exhaust shooting back into the engine bay. Any suggestions?

[5.0THIS]

Use a BFH and make it fit.

[BlackLT1Z28]

I guess I could try that again. But there is hardly any room between the EGR port on the header and the tranny dipstick bracket. We got a crowbar and tried to hammer it away, but no dice. And even if we do manage to clear it, there's no room to get the hardware in there and tighten it down. I thought there might be some time of filler out there that I could cover the hole with, so it could harden, and withstand the heat from the exhaust. I'll work on it.