I may have figured it out...turns out the clamshell is different, looks like the same for p10 vans as well.... I managed to snag a couple clamshells, but they are all 2wd clamshells, and they use a different frame mount from small blocks.
If it's allowed, I can post a link from 67-72chevytrucks, that has some pictures. Very hard to find pictures, was actually browsing YouTube and came across a video that had the different mounts.
I'd still be interested in pictures though, the 292 was losing popularity with the 350, so not a very common engine in the 73-87 trucks.
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