having done both routes, I preferred the simplicity of the zvh over the zetec.
however the power delivery of the zetec was much better and higher powered by far.
if you want reasonable power and a little originality then zvh, otherwise zetec all day long.
you've already gone over the top ex manifold, so not keeping it looking classic much.
there are a few high powered zvh's, but zetec produce more still.