Chevy small block 400 question.

My son and I just bought a small block Chevy 400 cu. in. engine for him to rebuild and install in his '79 El Camino. He's heard that .030 is the max.
you can overbore this block. Haven't got the heads off yet and we don't know if it's standard bore or not. Anyone know if this .030 max. overbore information is true? Thanks for any help.
Garrett Fulton
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yes
the reason is that there is no water passage between the front and rear pairs of cylinders on each side
that's how they managed to get 400 inches out of it...........max bore + minimum metal

max.
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Thanks. That's what I needed to know.
Garrett
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Make sure your cooling system is rock solid. New radiator, flush the block etc. As was mentioned, no water passages, then if you start upping the HP you start making more heat, and these are not known as cool running motors.
Big Chris

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block
motors.
My son's going to have it boiled out, line honed and bored with torque plates. Already has a new radiator on the El Camino. He really wants to get everything done right. However, I can't understand why all the aftermarket overhaul kit suppliers that we can find only offer .030 oversize pistons. If .010 or .020 would clean it up after we get the heads off Monday, that's what he'd like to to.
Garrett
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Um I am thinking ya'll need to check your info a little more. I am running one in a 78 cheyenne right now that is .06 over. That is the max that you can take them. I don't suggest it but you can get pistons for that bore. Partsamerica.com has a set of .06 for 104.99. I suggest you change your rods to the 5.7 instead of the 5.565 stock rods. This will cure some of the over heating problems. You also have to change the pistons to match the rods though. Also look at Northernauto.com. They have lots of parts that are harder to find. .03 is your basic kit you can get for a 400 sb.

HP
get
aftermarket
that's
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running
the
Thanks for the input. We read this .030 max. overbore deal in a Chevy small block overhaul book and from a Car Craft article about Chevy small blocks. A couple fellows my son knows also told him this. I'd like to think it's not true. I do think the longer rods are a good idea, also. I'll check the Northernauto website.
Garrett
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They say to not go over .03 but honestly if you are not building for major horsies then you won't have a problem.

you
bore.
that
small
the
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max.
TRW makes standard cast pistons in Std, 20, 30, 40, and 60 over. Part number 400NP. And, forged pistons in Std, 30, 40 and 60 over. Part number L-2376F.
They also have the rings for all those combinations, and about any other part you will need.
Al
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to
overbore
number
L-2376F.
Thanks Al.
Garrett
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