The original 350 in my 70 truck was a 2 bolt main. I threw rod through the side of the block at about 78,000 miles. I put a remanufactured long block in it with a 2 bolt main. The reman has about 100,000 on it. I know the previous two owners after me drove the crap out of it. I expect it to fail soon. With unleaded gas, everything in the later engines were upgraded. If it's an 80s engine I would run it till death or until it's too worn to perform. Then get the crate. But I wouldn't put any money into it. How many miles on it?
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