The Mk III (Phase 3)Shackleton used to run AVGAS through a couple of Vipers under the outboard engines for increased take-off performance. The thermal distress meant they were binned after about 150hrs?? (which was a fair number of take-offs....)
Your avgas was likely a highly leaded fuel (pre 100LL), right?
The problem here was lead contamination of the metallurgy of the turbine blades & nozzles, I believe. C-123K's similarly had J85's in pods outboard of the R-2800's. KC-97L's and B-36 production models also had J47's in outboard pods, and all had the same problem.
I should think 100LL alleviates that problem, but perhaps not completely.