The largest I've seen is a 450 SBC Stroker motor. This is achieved with a 400 block with a 4.125" stroke crank, 6.125" rods, 4.165" bore. This site HERE sells kits for stroked and destroked motors to give you some ideas.

 

A regular 400 stock block with small block cam location with all the work done is a 434, with small base cam.
On a new block from GM after market tall deck revised cam location, a 504 has been made by Sonny Leonard, and Bill Mitchell ( making a 454 SBC kit in last weeks NHRA mag).
The other motors from the above posting use's the aftermarket tall deck revised cam location.
I have built a 427 sb thats in my vette.

 

Well, some of you got close (1BAD80 is the winner).

What I know has been done and run well is a 481. The current theory is that with the blocks that are currently available, we could go to 509, but then you are talking about a bore that is like 4.310, so everything is getting a little thin.

I will provide more details if needed.

 

Would´nt the pistons be wider than they are tall, or can they be made tall enough to not rock in the bore, and still not interfere with the crank?

 

On a stock SBC block 4.155 is max in most cases with 4.185" possible on a few. At that the walls are around .125" thick and would not take alot of cylinder pressure. 4.00" stroke is max. 4.310 bore is impossible on a SBC. You would have no cylinders just water jacket.

Cstraub

 

On a stock SBC block 4.155 is max in most cases with 4.185" possible on a few. At that the walls are around .125" thick and would not take alot of cylinder pressure. 4.00" stroke is max. 4.310 bore is impossible on a SBC. You would have no cylinders just water jacket.

Cstraub

You can build a 454 SBC whit World Casting block
can be bored safely to a maximum of 4.200
leaving a .50 thick cylinder wall

 

The gentleman said stock GM block, and yes a world will go to 4.200, but it does not have .500" of cylinder wall, that would mean a full 1" between cylinders. . .not going to happen.

Cstraub

 

The gentleman also said in his posting,
Quote: I heard once of a 427 cubic inch small block, or something close (like 422). I have also heard of a small block 454, but I think that is with an aftermarket block.

We gave him both answer's, instead of a criticism of a posting.
Man no one want's to be wrong ain: :drunk:

 

I think I remember reading that most af the aftermarket blocks would go to 4.25 but no one made a head gasket until Fel-Pro did recently. Going .060 over that I haven't heard about. And does a 4.25 stroke require a raised-cam, spread-pan-rail block? I'm pretty sure it would. Where can I read about this 504 inch?

The Vandal

 

Sonny Leonard built it back in '94 . It was in a hot-roding magazine a few years ago using after market parts.
One thing on GM, part's cost more but their block's are machined for the stroker along the pan, reinforced block's and have the raised cam journals so the rods don't hit.
GM's SPO part's is now open to the public at certain dealer's and the price's have come down on all part's. FYI
I'll try to find it somewhere.
Sonnys site doe's not say anything about it, just being the first one to build a sbc over 500 cu. in 94

 

I just noticed that CN Blocks offers 10.00 as an optional deck height, which is probably the largest you can get.

 

i guess I should have been more specific...all i'm lookin for is how big can I get with a bone stock 400ci sbc just from boring out and installing a larger crank.

 

434.

 

4.155" bore and 3.875. Would be the largest
safely. I have had customers put a 4.00 stroke
and go 4.165 but to bore a stock block this big
is rare, had to be a good casting with no core
shift, and to put that much stroke requires a ton
of clearance work and special oil pan that can
get expensive.

Cstraub