Adding 2 more cylinders

[Chevy nutcase]

I hate how my brain works sometimes. When I bought my 66 c10 and saw how well the 250 ran I had I long discussion with my brain that we will never have to swap out the motor. It's not fast but an inline 6 has a charm to it especially when most have been pulled in favor of their bigger cousins. But here I am anyway thinking how far a v8 is going to bury me financially. Back when I was a teen and didn't have two nickels to rub together I always did cheap rebuilds getting a $100 kit from summit and never having professional machine work done and hope for the best. They always worked but I cant do that anymore so do I find a crapshoot motor on marketplace, have it professionally machined, spend a thousand years gathering parts or do I get a crate engine? I have no idea what the going rate is for a block to be pro inspected and bored if necessary so I'm sitting firmly on the fence right now