SBM Main Cap Material

I understand how to make a main cap. The question is is it worth it. My answer: nope

For someone doing it for business or whose spare time is critically limited, I would agree with you. But in my case I love jobs like this. It’s part of the reason I have the machines in my garage. I got this standard bore block cheap enough that even with material and line boring costs I should be into it less than $500 all in ready to drop the crank in. Pretty hard to find a decent 340 block for that anymore.
If you had seen the shop this block came out of you would understand how the caps could get lost. It was a complete disaster two-stories deep.