Hi,

I have a 1965 400 "B" block that another CO member would like to rebuild.

After I took it apart, I found out it was already bored .040 over.
The problem is that all the cylinder bores have scratches in them. The scratches are deep enough to catch a fingernail.

Not wanting to sell a real nice 500LB garage ornament. Does anyone know what the max overbore for this block could be?

I know the block could be sleeved but wouldn't that be costly?

Has anyone used 425 pistons in a "B" block? This would require a .125 overbore.

Thanks Much,
Tony

 

.060 shoud be fine, if you can find pistons!
.125 is a no-no unless sonic checked, and you still get very thin cyl. walls -
My chev 301, [283 +.125] ran hot all the time, and lost power when over 160 degrees!

 

Not to worry Tony...I know what Im getting into...while those blocks are not too hard to find in your neck of the woods they are up North so I have to pay a lot more than you guys to get some things done.

If it has to go over .060 then sleeves are it...150 to 200 a hole. Not worth it for you southern folks but it is to me. Im not rich and most would say Im stupid for spending that much on an engine block. Im trying not to add up the expenses of all this.....If it turns out to be a turd thats my fault..

 

sounds like .060 would clean it up if thats all that is wrong.
you can use 350 Olds pistons,but i wouldn't use the deep dished ones.
the piston size is 4.057 for a std 350.

 

I have done 350 Olds pistons a couple of times. It is a easy fix for your block. I have even done a .030 over 350 Olds pistons. std pistons make a nice 410 cid and the .030 over makes a great running 417. If you use the speedpro or the old TRW's make sure you use .005 piston to cyl wall clearance. If you go by the spec sheet, you will score the pistons and will run hot and hard to start when hot.

Gene