Mr C (i am imaracing700!)......this engine would have taken 600bhp as thats what i built it for!.....IMO it would be bullet proof @ 400bhp BUT i certainly aint goin to say it wont let you down...no such thing as reliable in Cossie you pay the money you take the chance...just being honest..TBH i would prefer it if the buyer took it to a pro and reassembled it...as then YOU got piece of mind..I had piece of mind it was right for ME.