I've seen some examples that this has worked out well on --- I have seen some pics In the Centurion Ironman thread of old IM's with modern groups and threadless setups , and it looked good,

but those had the whole kit -- modernish wheels , brifter groups , etc.

On the OP's bike (or what we can see of it) -- I'd rather use a Technomic if getting some more height was needed