350 block with 060 over bore
 

As the title says I have a pair of 350 blocks that came into my garage already bored 060 over. Every Chevy book says that a service limit on Gen 1 350 is 60 mills max overbore. Even at 60 mills over the cylinder wall thickness can be dicey depending on a casting. Before I load these spent blocks and take them to recycling yard I wonder if anyone have tried to re-hone and re-ring a 60 over block. I know it is not worth the effort, but I am just curious what one can get away with a bind.

//RF

Re: 350 block with 060 over bore
 

sleeves ?

Re: 350 block with 060 over bore
 

If the cylinders are round with no ridge at the top they should be able to be honed with no problems... Are they just bare blocks or do they have pistons, crank etc?

If complete, you basically would do a ring and bearing job and have a fresh motor although one that is at the end of its life.

Its probably cheaper to buy a block now than to sleeve what you have.

Re: 350 block with 060 over bore
 

They do make .080 over . just not my cup of tea...

Re: 350 block with 060 over bore
 

One block I tore apart - it had a number of issues with bearing being rough. This one is shot - look like engine was overheated, had a blown gasket and coolant contaminated oil turning it into sticky goo. Bottom of the oil pan was a mess! I will be one happy camper getting this mess out my garage.

Second engine has cast, dish style pistons and re-using them with large smog style heads (72 to 75cc) will result in low compression 7.5-8.0:1. Even later 64cc heads will increase compression to about 8.9:1. I am only guessing at the size of the dish. Condition of bearings is unknown.

The ridge (in both) is very small, barely noticeable. I have heard of 080 pistons, but I have never tried them before on any of my builds.

I think both engines had less than 25-30K since rebuild (what a shame). Sleeving is too expensive and in the end finding a untouched core is better and cheaper approach.

Thank you for feedback.

//RF

Re: 350 block with 060 over bore
 

Scrap prices are up. Send em to the yard. Theres too many good 350 blocks around everywhere to bother messing with something that is .060 over. Usually at .060 over if they were sonic checked they would be too thin for service. I couldnt even imagine trying to go .080 over. Besides that the old blocks are a thing of the past. The junkyards are full of the 87-95 throttle body engines. The blocks are already roller cam capable. They wear extremely well and have a 1 piece rear main which leaks a lot less.

Re: 350 block with 060 over bore
 

Just IMO but 60 is already beyond useable!. But..... If the one can be honed , re-ringed and put back together as a low compression / low power 'somebody needs a motor CHEEP!!!",, why not!!!, If it takes ANY work at all to get the bores in shape,, I'd call it scrap. 4" cores are too plentiful and cheap to waste $'s on anything but a bare-bones $500 rebuild. I won't use anything past +.040 myself in a stock block.

(edit,, danggit,, Cableguy treed me again :) )

Re: 350 block with 060 over bore
 

Adding Hardblock can be done but it reduces cooling capacity, so yes junk them both.

Re: 350 block with 060 over bore
 

Looks like majority agrees that long term reliability is very questionable for a 60+ over block. ;)

OK - I'll call my local JY's see what they pay for scrap iron. The only plus from all of this is that now I have multiple sets of heads, push rods, con rods, oil pumps, cranks, oil filter adapters, etc which could be potentially re-used.

//RF