On my build I am using a Mark2 donor, this is because one turned up at a local salvage company for a great price. The Westfield kit uses a Mark1. So far no issues, but, the exhaust manifold is completely different and doesn't come close to fitting the Westfield exhaust system. Called Westfield who offered to have their exhaust supplier make me a bespoke manifold. Great offer but maybe expensive. Checked online to see if the Mark1 manifold would fit my engine and get conflicting info. Decided to give it a try and ordered a used manifold today from Ebay for £30. This could go either way. Will get some photos online when next at the workshop.