What is the most I can savely overbore my 1969 440 block to (.060)?

[1Bad70Charger]

Probably will end up rebuilding my 1969 440 engine this winter and what is the biggest overbore I can safely do I know .030 is the most common and is a no brainer.

As long as the block is sonic checked can I go out .060 as I want to get the most cubes out of this engine to build a 550HP 440, without having to stroke it.

What's the largest I can overbore the block and what cubic inch displacement  does this get me to with a stock 440 c crank?

Also, how does one get to a 470 c.i. engine that I commonly see with a 440 block?

I also see 451 ci 440 engines performing great and I would imagine that is with a .040 or .050 overbore to get to 451 cubes?

Thanks in advance!  

[firefighter3931]

The sonic check will tell you how far you can take the block. A smaller .030 overbore is usually better for structural integrity and ring seal. The less flex you have in the cylinder walls the more power it will make. 

A .060 over 3.75 stroke 440 is 452 cubic inches


Ron

[Ghoste]

The .060 overbore also pretty much makes it the last rebore for that block.

[b5blue]

Yup! I had to go to to .060 to clean up my bores.

[John_Kunkel]

can I go out .060 as I want to get the most cubes out of this engine to build a 550HP 440, without having to stroke it.

The .060" overbore might possibly net you a loss of power compared to the .030" overbore due to the loss of ring seal Ron mentioned. Not worth it IMHO, stay with .030" or even .020" if possible.

[maxwellwedge]

Some have hit water at .030 due to bad core shift so get it tested properly, bore only as much as you need to and use a new crank to get the cubes. 

[1Bad70Charger]

Some have hit water at .030 due to bad core shift so get it tested properly, bore only as much as you need to and use a new crank to get the cubes. 

Looks like I won't be going over .030. 

[Rob R]

I frequently go 4.390 on 440 blocks...

[1Bad70Charger]

I frequently go 4.390 on 440 blocks...

How many cubes is that 447 ci?   

[six-tee-nine]

Good thread.....

I bought a cheap bare 440 block that was rebuilt .30 over but the piston to wall clearance was set to smaal so the walls got scuffed. I was hoping to still use that block even if I have to get it bored up to .60 over for a mild 512 street stroker.

[b5blue]

Just check it for "core shift", I have had no issue's with .060 on my build. Be sure to have the exact spec. for your pistons bore requirements. 

[maxwellwedge]

As long as the core shift is good and the block checks out ok you can go 030+. I said earlier that some were so bad the people hit water at 030....so "call before you dig".

[TylerCharger69]

There is also the option of resleeving   If the cylinders clean up at .030  then thats fine...I wouldn't bore any more than necessary just to get more displacement.