Obscure casting numbers

[MrMarty51]

The casting numbers on this block were mighty sloppily cast from the factory.
This is a four bolt main, can anyone tell Me, is this a 350 or is this a 400.
I was told by the old timer that bored the block that it is a 400. I have no inside mics. so I cant measure the cylinders.
It did clean at .030 over.

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[MrMarty51]

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[bucket]

I'm not good at looking up the suffix codes like other folks are.

But here's my simple minded thoughts. Did the fella bore the block like it's a 350 or a 400? It's impossible to bore a 400 block to 350 specs, unless maybe it got sleeved.

What's it look like when you hold a ruler to the bore? It should be obvious if the bore is well over 4 inches.

 

[mtnmankev]

The center two cylinders on each side are siamesed in a 400, no space between them for coolant to flow.
Also, find the flat surface behind the alternator for the stamp that ID's the engine, that code should tell you what engine size it is and what vehicle it was originally installed in.

 

[MrMarty51]

Thank You guys for the reply.
I`ll get over to the shed and do some measuring of the bore and check to see if the center cylinders are siamesed.
It had been so many years ago since the block had been bored, and the old timer has passed on, that I dont know. I do know that I had taken a 400 block to Him that I was not going to use. he did bore it and was very happy when it cleaned at .030 over. I am not sure if this is that same block or if He had used the 400 and this block is from something else.

 

[DanMcG]

a look between the bores will tell ya if it's a 400. look for the steam holes.

https://www.enginelabs.com/news/steam-holes-the-cooling-mod-for-400-based-chevy-small-blocks/