my thoughts on running it in next time
remove the turbo exhaust and use a standard exhaust put filters on the carbys and run it in as a normal engine for a few ks
then once its run in then comence putting the turbo system on. may have a better survival rate ....my turbo runs very rich indeed but when it comes on boost it certainly uses a fair chunk of gas ,Id be more inclined to say it was lean and timming .