www.cosworth.com and follow links for sales and engines for a catalogue of yb engine parts. much cheaper than ford for most parts.

to order, call Jeremy Scott on 01604 598653. prices are ex. VAT and carriage is 8.50 for ANC next day.

no reason that you can't do it yourself if you're careful. the hardest part of the job is compressing the valve springs to remove the collets, cap and spring so that you can get to the seals. if you can do this with the head still on (using compressed air to keep the valve closed), it's your best bet. otherwise you need new head gasket and bolts and the cost really starts to mount up.

if you've got the right tools, it's an easy diy job and can be done with the head on.