Thread: chevy small block 400

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hi i got a 400 small block from a friend he say it ways running when he took it out.The thing is we broke it down the crank looks ok but we do not know if its std. or 10/10 or 20/20 its looks like its the crank thats came in the motor years ago how can i tell if its a std. crank or not.The bearings just got gm 400 on them and an A200 0005 0s

Std....and most if not all crank grinders will stamp what the grind ended up being on the crank itself. I'm curious to see how lucky you got, What is the number cast into the side of the block?

what u mean on the back or the side

You will probably want to have the crankshaft checked for wear, so take it to a machine shop and have them measure it with a micrometer. That way you will not only know how much it has been ground, but also if it needs to be ground again.

what u mean about the cast number

on the side of the block

the cast number on the back of the block is 3951511

does 511 appear on the side?

i didnt see it just three freeze plugs

okay, it's still a 511 block. not a bad piece to work with. you can have some fun with it. it is a 4 bolt main if I recall.

its a 2bolt

will the crank have somthing on it to let me know if its a std. crank or not

okay. 511's came as both versions. The three freeze plugs in first production years were supposed to designate a four bolt block. Personally I like the two bolt series of that block. More room to play.

The bearing number you wote is Factory undersize 0.0005. So you need to check for wear and if it check ok go with Half set of 0.001 undersize and the other half STD therefore put each half in the engine you will have a set of 0.0005 under bearings set.

Better yet, grind it. It's seen enough service to warrant it.