My 69 bus had original black fire protective / sound deadening type paneling clipped in above the engine but it's pretty wavey and if you bent it it cracks .What do most peeps use if anything at all to replace it.
I've just replaced mine with something called Supalux. Its water and fireproof and it's dead easy to work with. I put it over a layer of 12mm fire retardant sound proofing to try and keep the noise down a bit.
Click on my build thread link below and have a look on page 4 to see what it looks like.