273 302 318 340 build

Yes on the ease of measurement for your tools. I use the telescope gauges mainly just on piston bores; I am good to maybe .0005" accuracy there. Since I don't do actual boring or piston fitting, I let the shops do that accurately with their better tools, and just do wear and QC checks. Occasionally I'll use them on other odd things. They are just too hard to use and get accurate results on the bearings. Plastigage....

And be aware that calipers have limits on accuracy too. You are now working in the range of accuracy where micrometers are really what are needed. (I measure my bore gauge settings with micrometers only.)

5 generations together is pretty rare!