Stumbling Slant --what is left??

"Quench" is sometimes used to mean the shape of the combustion chamber/piston top. "Quenchout" refers to dead(ish) zones created by relatively cold metal and poor mixture access that tend to impede the fire: the space between the top ring and the top of the piston…spark plug electrodes shrouded by nearby cylinder head metal…that kind of thing.

Yeah, you have to have room for these plugs. They'll work in a stock/ish Slant-6 or LA motor…in a 2.2/2.5…in a 3.0 Mitsu V6…probably in A-motors and others, too, but I haven't checked or tried. Less negative deck height or extensive head milling or other changes will require checking to see if these plugs will still clear everything, but if you're making those changes, you'll probably wind up wanting a colder plug anyhow, and these projected-electrode plugs come in one step colder, but not two.