From what I remember the Landy system is restrictive, you'd be better off getting a custom 2" system installed.
That's what my uncle did back in the 80's with his 186 conversion on his S3.
Actually prior to that he ditched the 2.25 manifold and exhaust, added a set of Perry headers and 2" exhaust and the old Rover engine came alive.
When he installed the Holden he mated the 2" system to the Holden manifold.
Bookmarks