I’m not sure there are many XKEs with American V8 conversions. Mostly it was done to later Jag XJs because their resale value was so low (due to poor reliability).
Earlier, before E-Types were rare, it was easier to put in a small-block than it was to fix the 6-cylinder OHC 3.8 or 4.2. These days, no one would do it.
AH 3000’s like the one pictured here were fast for the times. 0-60 in about 10 seconds and a top speed of maybe 120mph. (Somewhere in between Triumphs and Jags) They just were pretty primitive under that beautiful body.