Trying to get my head round these. 1971-1972 OIF A65. I have looked at many that are advertised. Which were fitted with balance pipes as standard. I am rebuilding a basket case that came with no pipes at all. Not too bothered about price difference. Any pictures may help just want to make it standard, mine is the Thunderbolt. Other forums are too quiet so I keep using this one and do get results, thanks lads.