typically speaking, were most filled combustion chambers in iron heads achieved by simply filling with weld or brazing in an iron "slug" such as those available back in the day, (made by Speed Gems or somesuch); and, what are the pros and cons of either method?
I remember filling Chevy 6-cylinder heads by welding. Miilling the head didnt raise the compression ratio that much because of the size and shape of the combustion chambers. Just lots of weld, and you had to know how to weld cast iron - heat the head before welding, use nickel chrome rod, and cool it slowly after. Installing pop-up pistons was the better way, but expensive. We used to mill Ford flatheads because that was the easiest way to raise the compression ratio with them. We didnt all buy those fancy finned aluminum heads. Couldn't afford them. One thing you had to do was to fly-cut valve clearance in the heads after milling needed a buddy at a machine shop for that. And relieving the block helped breathing, but lowered the compression ratio. Lots of hours with a Dumore grinder. Still have my Dumore out in the shop. Johnson adjustable tappets long time ago.
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