I am very familiar with this Buick engine having re-built numerous renditions in BL platforms , Landrover being the most prevalent and still we see them today.
Used in what was called the B-O-P cars, Buick, Oldsmobile, & Pontiac it was indeed 215 Cu Inches or 3,5 litre displacement.
Parent company GM shelved the unit in favor of the C/Iron GM small block due to porous casting technology problems at the time where 95% of production was scrapped , the Rover Car Company purchased the rights and put that problem right.
What they couldn't put right due to the compact block architecture was coolant flow ports from block to head. Being an end flow coolant jacket design middle cylinders tended to run hotter than the end pots.
The Achilles heal service experiences (and still are) was overheating and block expansion issues which left those middle cylinder liners to create internal coolant leakages into the combustion chamber when the engine was heat distressed. In many cases repair shops diagnosed the issue as a head gasket problem when in fact it was block failure due to overheating distress and abnormal top deck block permanent expansion.
This led to expensive repair bills for owners and the Landrover Discovery/Range Rover platforms didn't enjoy the best reputation as it should have.
Having sawn a block down the middle you can observe various production solutions to inherent problems of cost, production conformity and long term serviceability in the face of changing power and emission requirements over the life of the engine in terms of development and competition.
Taking Dave's example of replacement cylinder liners prevalent in many manufactures designs of the 1950's & 60's . The solution was elementary. Rough machine the parent bore and insert a pre-manufactured liner with matching piston from a specialist manufacturer often from off site sources for a pre -set production cost run. . The parent block needing only cheaper machine tools to cut the parent bore with a wide range of acceptable tolerances. That meant lower skilled machinist & tooling overheads as well. Since most liners were of the top hat design they were more or less a push fit into the block and the liner sitting on a block recess register to prevent it slipping down and colliding with the crankshaft. Apart from maybe needing a shim under the liner register step the engine could be easily assembled with low skill operatives further reducing your production costs.
Now by the 1970 emission issues come to the fore!
Apart from a new set of cylinder liner finishes to contain oil vapor carry over with new piston ring designs, the cylinder liner had to be a much tighter fit into the parent black in some cases as much as 0,01mm (0. 004') The was done to get greater heat transference from the liner to the block with much tighter tolerances in the parent bore and the top register was eliminated due to thermal distress and circumferential cracking of the liner in service.
This of course pushed up production costs since distortion was problem requiring production line honing to a preset cross hatch finish.
The Buick design had none of this!
Rover ran with it to the very end taking the engine to 5,2 litres displacement in some non production line specimens.
In this innovative design
The cylinder liner was a simple pre-finished sleeve pressed into the block which was open top the coolant jacket. Hence a semi wet liner design. To retain it in place there was a step at the bottom of the block to prevent slippage sealed by an O ring, and the top deck was similarly sealed with the top rigid deck of the block giving its integrity.
Over the years B/L extended the block skirt introducing flank girdling as you see today with all modern blocks including MB designs.
Heat of course is the killer, but the design ensured lower production costs and easier manufacture. The Discovery 2 as an example that ran out its production run in 2004 as a 4,6 litre unit under BMW ownership.
The heat problem was never really addressed which ostensibly was permanent expansion of the top deck, made worse by overheating distress caused by owner servicing neglect' Ultimately leading to destruction of the top sealing O ring and carbon particle penetration down past the liner to block register interface casing distortion. Consequently I don't see these engines going past 250,000 miles without an overheating issue.
Nonetheless not bad for a cheap to produce engine that met all US emission regs through 2005 and the units foundation remember was in the late 1950's.
Today of course with fusion block finishes these issues I have pointed out are eliminated. The down side is that the block is no longer serviceable in the old sense of the word. When its worn out or damaged its simply a disposable item . In short the engine of today is a Woolworth's special
On the other side of the spectrum is the inherent cost to produce modern designs.
Simply put they demand very high precision machine tools like say Haas Inc.
Regrettably no longer can a budding Henry Ford or Andre Citroen set up a back street shop on a limited budget.
Of course if the motor trade has been in your blood like me I have often dreamed of the snorting but musical running "Boccharini Super" sport car production plant .
The word is venture capital in the millions and no promise of success & profits in today industries of yesteryear.
Here is one of my favorite machine tool manufactures--Haas Inc--Made in the USA!
Each machine tool starts at about $250,000, so you need deep pockets to produce that Boccarini Super.
Dennis.
https://www.youtube.com/watch?v=WTEGAjj_SAs