So. Unlike most british engines American engines dont have adjustable rockers. Once the heads are on and the rockers are positioned correctly to give a central contact spot on the valve the required pushrod length needs to be ordered and fitted. The tool needed is a pushrod with a threaded end. Each turn is 0.050" so the total is added to the base length of the tool. I ordered the tool from the states. It's the size of a longer pencil and was $13. Add post and vat it came to over £50!!
Heres the annoying bit. I've just ordered 16 9.560" pushrods from the same company in the states. They are $39. Total including shipping and VAT.... £48... what wierd calculator do the Yanks use??