I believe your info is a bit fuzzy. 67 blocks were definitely VIN stamped, memory (which is also a bit fuzzy) says VIN stamping began in 59.If you knew the engine's history it would be better,but yeah,drilling the accessory holes can be sketchy.
For contrast,I sold the 283 out of my 67 chevelle about 4 years ago for 400 dollars.62K original miles on it,didnt smoke,knock,or ping.
Guy needed it for his chevelle resto.Small blocks weren't stamped with a vin back then,just the BBs,so it was perfect for his 67.
Was a good strong motor for what it was.Did not like the giant can in the lifter valley,lol.Had a clearance issue when I put a dual plane on it.
Also had to put the lead additive in it every gas fill up.
Now, go hunt down a rebuildable core L31 Vortec (or a crapped out truck that has one) --- that's what.Welp no deal on the 305. We had agreed to meet today at this "internet exchange" location in front of a small police station in town. Guy messages me this morning saying that he forgot he wasn't going to have his truck today and that I need to come get it about 50 minutes away. I have yet to respond. IDK what to say or do.
Yep, It's been my experience when people say stuff like that they don't want to deal with explaining why or how. I hate when people tell me what to do or not to do in a case like this. Just explain the pros and cons and let me decide. I have my big boy pants on.When people with years of experience say something like that, I question their experience.