Just curious, a 1968 g block 400 has a bore of 3.870. Has anyone ever bored one out to 4.000 or more? Can it be done?

 

No one has ever posted that they did. There's an old thread on ROP about it. Rumour has it the cylinder walls are pretty thin. The casting is different for a 455. A 400 G doesn't have just have the same casting with thicker sleeves


edit:

here's the thread:

http://www.realoldspower.com/phpBB2/...ckness&start=0

and a couple people said they have

Here's another one on Classicolds:

https://classicoldsmobile.com/forums...red-455-a.html

 

A good auto machine shop can sonic test the walls for thickness and tell you what the safe overbore would be. then you will probably have to buy custom pistons like CP, which you might be doing anyway if you are looking for the max bore size and power.

 

Thanks guys...