Posted this in a different section w/no replies so will try it here. Hopefully someone has a car w/an orig. or an old radiator top plate w/an original '70 350 High Compression Manual Transmission Emissions decal. I haven't checked the parts book &/or Assy. Manual but I assume Skylark w/HC & 3 on the tree or GS w/ 3 or 4-sp. would be the same decal & that LC 4BBL Skylark w/3 on the tree would be different.
I've seen these cars pop-up now and then for sale. I would assume that the Owner would take a pic and send it to you. I remember way back when I was a teenager, there was a decal repo place - Jim Osborne Reproductions, or the like and he seemed to have examples of engine compartment decals that were far-and-few between compared to other Vendors.