Anyone for a mash up - overdrive on sale too elsewhere...
https://www.ebay.co.uk/itm/Rootes-Sunbeam-Alpine-Overdrive-Series-4-Gearbox/332457060614?hash=item4d67fc2906:g:pWkAAOSwdSRaChxh
So I share my baby mechanic steps to encourage others.
One manifold gasket changed and my engine is running sweetly again.
Happy days. Thanks for all the advice.