The Mini Cooper Forum was set up in 2016 with a view to providing a discussion and information platform for classic Mini Cooper and BMW MINI Cooper enthusiasts around the world. However discussion on anything to do with the Mini/MINI has always been welcomed.

As the forum banner says it is an independent forum with no affiliation to any car club or business. In terms of operation the forum has worked well with very few problems. However it’s fair to say that the forum has not been a success. Quite why remains something of a mystery. With this background in mind we hereby give notice that a final decision as to whether the Mini Cooper Forum continues to run or is taken down will be made on or just after 30th November 2019.

If you have ideas of how the forum might be improved to attract more discussion please feel free to either post on the forum or email

Graham W Robinson
May 2019

1990 998 John Cooper Conversion cylinder head

(1990 – 2000)
User avatar
Posts: 31
Joined: 17 Mar 2017, 15:06

1990 998 John Cooper Conversion cylinder head

Postby cooperd1970 » 06 Feb 2018, 15:51


I have an original JC conversion that has been fitted to the 1990 Flame that I own. It has been on the car since the car was purchase from Rover (Swindon) in Nov 1990.

I wondered if anyone has any information on what the inlet port size is on these heads? Or were different heads used for these kits which means the ports vary in size? I believe that they were made by Janspeed for Cooper Cars, but have also heard that companies like MiniSpares were also commissioned to work some of them. I am also led to believe that they were classed as Stage III heads?!

I know that there is a JC Conversion Facebook page, but I have never been a Facebook member {and never want to be}. So can't ask the guys there, unless anyone on here knows another method on contacting the owners of the page {maybe one is a member here}!

I'm thinking of fitting the Maniflow inlet manifold in the near future and they supply two different port sizes for twin 1 1/4 SU's and I don't know which one I require.

Any info/leads would be appreciated.


Return to “Rover Cooper”

Who is online

Users browsing this forum: No registered users and 1 guest