When I had the SUs rebuilt by Rhys I don't remember how or if we arrived at what needles to use, but there are needles in there, so It would be easy enough to figure that out. I'm glad you mentioned the potential for damage. I'd like to avoid that for sure.

The more pressing questions are:

How or is there a way to determine which injected head I have? If the answer to that is yes, then once that was known would it be possible to match it to the correct bore?

Is it only the bore that is in question? Does the stroke also play a part? Seems they would both be pretty easy to measure with the head off. .

I have the original B18 long block from my '62 in an official Volvo, folding plywood crate with it's steel skid sitting in my shed. I was going to try and sell it, figured the crate was worth more than the engine, but maybe it would behoove me to take that head and just have it redone. If it was decided that would be the way to go, would the cam and bore/stroke information be required before any work commenced?