Some time ago, I mentioned the D7 engine needed work; after I'd had the bottom end reconditioned I fully intended to have the barrel rebored and a new piston fitted but never got round to it.
Yesterday I decided it was time to go ahead with my original plans and, as I had a spare barrel which had already been bored out to +060" I ordered a suitable piston from Rex Caunt Racing (service second to none!), which I received this morning complete with rings, gudgeon pin and circlips. (Thanks to Debb, Rex and Steff)
In the coming week, I shall take the barrel and piston to a local engineering works who are performance engine specialists and get them to check the piston to bore fit and hone the bore as necessary.
The piston seems quite a snug fit (there should be .0077" - .0078" clearance at the top of the skirt and .0038" - .0039" at the bottom of the skirt), so it will need measuring accurately.
Or remove my original barrel (+020" oversize) and have it rebored to take the new piston.