Here's a salmagundi of interesting stuff I've found in researching the history of V8s in Healeys:
MG related:
MG V8 beats a Vette:
Healey stuff
Max Balchowsky's 283 Chevy swap into a Healey 100 featured in Hot Rod magazine in
June 1956
A big block Healey first done in
1957
AC stuff
From Trevor Legates "Cobra - The First 40 Years"
BEX 327 - ordered from AC and shipped to the US and fitted with a Corvette motor in
1957 with various body mods later seen on the Cobra:
Here's a link to the whole story, but it's best to access on Google Chrome for a translation.
http://www.cobracars.be/bex%****7.html