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Discussion Starter #1
Is there any reason a 4340 forged steel crank from a 400 couldn't be ground .200 on the mains so it will fit in a 350 block? I've done it before on a stock cast 400 cranks but I have an aftermarket forged steel crank from a 400 that is actually 3.8 stroke that has spun center mains. I'd hate to see it wasted so I was thinking of having the mains ground to 2.450 so I can use it in a 350 block or maybe back in a 400 with the use of bearing spacers. (this crank is probably to bad to turn .010, .020 or probly even .030). Not sure if the crank is Scat or Eagle. They both seem to use the same part # thats on my crank (440038006000). I cant think of a good reason not to do it but maybe I'm missing something? Thanks for reading.
 

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It should be fine. -And better than turning a cast crank.

However, the cost to turn/grind the mains down is likely to come in at about the same cost of a new 383 crank. It may not be financially viable, even in possible and plausible.
 

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I think it would depend on if the crank was surface hardened on the journals and if the crank cracked due to overheating on the mains.
 

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I would worry about the oil holes becoming too close to the edge but you should be able to judge that. It's probably ok.

The stones on a crank grinding machine won't care if the crank is cast, stock forged, or 4340.

Cost to cut down the mains should be way cheaper than a new stroker crank in the hands of an experienced crankshaft grinding shop.

We used to cut down the rod journals on 350/327/302 cranks by .080" with an offset grind to change the stroke, and while it cost more that turning a crank .010" or .020", it was still very cheap compared to a new crank, even if it came from China.

So find a good crank grinder and have at it.
 

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I would worry about the oil holes becoming too close to the edge but you should be able to judge that. It's probably ok.

The stones on a crank grinding machine won't care if the crank is cast, stock forged, or 4340.

Cost to cut down the mains should be way cheaper than a new stroker crank in the hands of an experienced crankshaft grinding shop.

We used to cut down the rod journals on 350/327/302 cranks by .080" with an offset grind to change the stroke, and while it cost more that turning a crank .010" or .020", it was still very cheap compared to a new crank, even if it came from China.

So find a good crank grinder and have at it.
I had to go look to see how far off I was, going by memory.
I was operating under the assumption that a new crank would be about $350.
I forgot, however, that the 'cheap' Scat 383 cranks are cast, not forged. (Though I do see that both cast and forged cranks are cheaper now than last time I was in the market.)
I am also geographically handicapped here. There is only one (reputable) crank grinder within four hours of here, and their prices start at $300.
 

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Discussion Starter #7
I would worry about the oil holes becoming too close to the edge but you should be able to judge that. It's probably ok.

The stones on a crank grinding machine won't care if the crank is cast, stock forged, or 4340.

Cost to cut down the mains should be way cheaper than a new stroker crank in the hands of an experienced crankshaft grinding shop.

We used to cut down the rod journals on 350/327/302 cranks by .080" with an offset grind to change the stroke, and while it cost more that turning a crank .010" or .020", it was still very cheap compared to a new crank, even if it came from China. So find a good crank grinder and have at it.
I like that it is forged 4340 and also really like that extra .025 that I wont have to take off the decks to zero deck it. The few extra cubes wont hurt either. I'm hoping it turns out usable. I really want to put it back in a 400 block by using bearing spacers. Who knows, .030 might clean the mains up anyway. Thanks for the reply. I will take a look at those holes.
 
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