I want to run a pipe up through the roof, What are you cpnnecting to the engine with, Flexible exhaust?
To quote the Lister manual:
If a longer exhaust pipe than our standard bend must be fitted, this should at no point slope upwards from the engine exhaust port unless a groung silencer is fitted close to the engine, or a suitable ground tap is fitted at the bottom of the pipe line, which tap should be opened before the engine is started up each time, otherwise moisture due to condensation in the cool pipe will drain back into the cylinder head and cause damage.
Also, from personal experience, soot will build up in a vertical pipe and eventually catch fire