I got a 400 block, a 509 casting, in a package deal a while back. Unfortunately it has a pretty fair amount of wear and some rust in the cylinders, and worst of all, it's already been rebuilt and bored .040.

You could probably clean it up and use it but it would'nt be pretty. I'm not even sure that it would clean up correctly at .060. And I know that .060 is kind of pushing it with any block, especially a 400 even though I have run a 400 block at .060 before. But that block started out in a little better shape.

So, my question is, with the siamesed cylinders on a 400 block, can you sleeve the block and rebore to standard or .030 over? Or are the cylinders too close together?

 

I would wonder what the cost difference would be between sleeveing the current block, vs. simply replacing it?

 

You might be right. I try to keep my eyes open for good 400's, bare or complete and have managed to grab a couple at fairly decent prices. But sometimes they get kind of pricey.

 

Well if this turn out to be the only option i'd sleeve it.

 

If it indeed comes down that you need a new block, take a look at ebay.

Skipwhite has fully machined to your specs GM Bowtie blocks for $1250.

After the cost of machine work to a used 400 block you will be close to the $1000 mark anyways.

 

You would be much, much better off with the new Dart SHP block. Comes already machined except for the final bore size. With a .040" bore I bet the cylinder walls are flexing already let alone with a .060" bore. So you would be burning some oil and loosing power with blowby.

 

Mine is .060 over.

Depends on how much core shift. You can usually tell looking at the block.

-- Joe

 

You can get 8 sleeves installed to bring it back to new specs but in your case, you're open to other options such as an aftermarket or factory replacement block.

If you had a rare numbers matching block and needed it because of it's rarity or requirement of casting numbers then the cost of putting in 8 sleeves isn't bad. For normal use, the cost of getting 8 sleeves put into an old block isn't worth the little more you can pay for an aftermarket block which will be a much better casting. Stay away from the cheap chinese castings.

 

It would all depend on how much power your talking about building
the motor for.
At .060 as long as no core shift problems and not aggresive on power
works fine. Still running into wall flex, center bores especially. Head gasket sealing
under higher comp and heat issues also. Not motor heat but transfer
between already thin center bore walls.

At tear down we would very carefully check and inspect the
motors and learned alot about these blocks.
Also built alot of our older blocks for street use to recoup a few dollars.

After .030 we would stop and put them back into our haulers where alot
of them came from when new.

I'd go Dart or find better OEM. Years ago we were scrounging for good
ones and usable ones were hard to find then.
At that time had any where from 6 to 8 on hand.
70's cars 2- bolts/ Trucks 4- bolts where we got alot of them from.


HTH

Later

 

IMHO .060" is a roll of the dice and the odds are not in your favor.

 

Have to agree, as I never took one that far with or without
any power additions.

Quite a few running around though.

Later

 

Yeah.
There are a lot of blocks and heads on ebay that would make better boat anchors than anything.