I was talking to a guy regarding a 258 short block (he has two) and on top
of the pistons is the number 58 stamped into them on both blocks.

Would this be a .60 over bore or something different?

Thanks,

Bill

 

"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> I was talking to a guy regarding a 258 short block (he has two) and on top
> of the pistons is the number 58 stamped into them on both blocks.
>
> Would this be a .60 over bore or something different?
>
> Thanks,
>
> Bill
>
>

It's possible, but that isn't standard practice. Maybe the engine shop that
rebuilt the engine measured the pistons and they were .058 oversize, which
would be about right for a .060 overbore assuming .002 piston clearance. The
best way to know for sure is to have someone with the proper measuring tools
measure the bore diameter. For reference purposes you could even use a dial
caliper to check it and be within .001 or so, which would be acceptable. The
stock bore is 3.750 and .060 overbore would measure 3.810.

Chris

 

"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> I was talking to a guy regarding a 258 short block (he has two) and on top
> of the pistons is the number 58 stamped into them on both blocks.
>
> Would this be a .60 over bore or something different?
>
> Thanks,
>
> Bill
>
>

It's possible, but that isn't standard practice. Maybe the engine shop that
rebuilt the engine measured the pistons and they were .058 oversize, which
would be about right for a .060 overbore assuming .002 piston clearance. The
best way to know for sure is to have someone with the proper measuring tools
measure the bore diameter. For reference purposes you could even use a dial
caliper to check it and be within .001 or so, which would be acceptable. The
stock bore is 3.750 and .060 overbore would measure 3.810.

Chris

 

"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> I was talking to a guy regarding a 258 short block (he has two) and on top
> of the pistons is the number 58 stamped into them on both blocks.
>
> Would this be a .60 over bore or something different?
>
> Thanks,
>
> Bill
>
>

It's possible, but that isn't standard practice. Maybe the engine shop that
rebuilt the engine measured the pistons and they were .058 oversize, which
would be about right for a .060 overbore assuming .002 piston clearance. The
best way to know for sure is to have someone with the proper measuring tools
measure the bore diameter. For reference purposes you could even use a dial
caliper to check it and be within .001 or so, which would be acceptable. The
stock bore is 3.750 and .060 overbore would measure 3.810.

Chris

 

"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> I was talking to a guy regarding a 258 short block (he has two) and on top
> of the pistons is the number 58 stamped into them on both blocks.
>
> Would this be a .60 over bore or something different?
>
> Thanks,
>
> Bill
>
>

It's possible, but that isn't standard practice. Maybe the engine shop that
rebuilt the engine measured the pistons and they were .058 oversize, which
would be about right for a .060 overbore assuming .002 piston clearance. The
best way to know for sure is to have someone with the proper measuring tools
measure the bore diameter. For reference purposes you could even use a dial
caliper to check it and be within .001 or so, which would be acceptable. The
stock bore is 3.750 and .060 overbore would measure 3.810.

Chris

 

Thanks for the reply Chris,

I thought it unusual for two blocks to have the same stamp on the pistons.
Could this be a stock numerical representation? One of the blocks is an 84
and one is an 85. He said the current one in the jeep (85) has been driven
not much in the last 10 years since he had it. If true that would make it
going from stock to 60 over bore within 10 years. Possible but seems a
little extreme doesn't it?

Thanks,

Bill




"c" <c@me.org> wrote in message
news:K4%dc.27016$YC5.14309@twister.rdc-kc.rr.com...
>
> "William Oliveri" <wuji@bigvalley.net> wrote in message
> news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> > I was talking to a guy regarding a 258 short block (he has two) and on
top
> > of the pistons is the number 58 stamped into them on both blocks.
> >
> > Would this be a .60 over bore or something different?
> >
> > Thanks,
> >
> > Bill
> >
> >
>
> It's possible, but that isn't standard practice. Maybe the engine shop
that
> rebuilt the engine measured the pistons and they were .058 oversize, which
> would be about right for a .060 overbore assuming .002 piston clearance.
The
> best way to know for sure is to have someone with the proper measuring
tools
> measure the bore diameter. For reference purposes you could even use a
dial
> caliper to check it and be within .001 or so, which would be acceptable.
The
> stock bore is 3.750 and .060 overbore would measure 3.810.
>
> Chris
>
>

 

Thanks for the reply Chris,

I thought it unusual for two blocks to have the same stamp on the pistons.
Could this be a stock numerical representation? One of the blocks is an 84
and one is an 85. He said the current one in the jeep (85) has been driven
not much in the last 10 years since he had it. If true that would make it
going from stock to 60 over bore within 10 years. Possible but seems a
little extreme doesn't it?

Thanks,

Bill




"c" <c@me.org> wrote in message
news:K4%dc.27016$YC5.14309@twister.rdc-kc.rr.com...
>
> "William Oliveri" <wuji@bigvalley.net> wrote in message
> news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> > I was talking to a guy regarding a 258 short block (he has two) and on
top
> > of the pistons is the number 58 stamped into them on both blocks.
> >
> > Would this be a .60 over bore or something different?
> >
> > Thanks,
> >
> > Bill
> >
> >
>
> It's possible, but that isn't standard practice. Maybe the engine shop
that
> rebuilt the engine measured the pistons and they were .058 oversize, which
> would be about right for a .060 overbore assuming .002 piston clearance.
The
> best way to know for sure is to have someone with the proper measuring
tools
> measure the bore diameter. For reference purposes you could even use a
dial
> caliper to check it and be within .001 or so, which would be acceptable.
The
> stock bore is 3.750 and .060 overbore would measure 3.810.
>
> Chris
>
>

 

Thanks for the reply Chris,

I thought it unusual for two blocks to have the same stamp on the pistons.
Could this be a stock numerical representation? One of the blocks is an 84
and one is an 85. He said the current one in the jeep (85) has been driven
not much in the last 10 years since he had it. If true that would make it
going from stock to 60 over bore within 10 years. Possible but seems a
little extreme doesn't it?

Thanks,

Bill




"c" <c@me.org> wrote in message
news:K4%dc.27016$YC5.14309@twister.rdc-kc.rr.com...
>
> "William Oliveri" <wuji@bigvalley.net> wrote in message
> news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> > I was talking to a guy regarding a 258 short block (he has two) and on
top
> > of the pistons is the number 58 stamped into them on both blocks.
> >
> > Would this be a .60 over bore or something different?
> >
> > Thanks,
> >
> > Bill
> >
> >
>
> It's possible, but that isn't standard practice. Maybe the engine shop
that
> rebuilt the engine measured the pistons and they were .058 oversize, which
> would be about right for a .060 overbore assuming .002 piston clearance.
The
> best way to know for sure is to have someone with the proper measuring
tools
> measure the bore diameter. For reference purposes you could even use a
dial
> caliper to check it and be within .001 or so, which would be acceptable.
The
> stock bore is 3.750 and .060 overbore would measure 3.810.
>
> Chris
>
>

 

Thanks for the reply Chris,

I thought it unusual for two blocks to have the same stamp on the pistons.
Could this be a stock numerical representation? One of the blocks is an 84
and one is an 85. He said the current one in the jeep (85) has been driven
not much in the last 10 years since he had it. If true that would make it
going from stock to 60 over bore within 10 years. Possible but seems a
little extreme doesn't it?

Thanks,

Bill




"c" <c@me.org> wrote in message
news:K4%dc.27016$YC5.14309@twister.rdc-kc.rr.com...
>
> "William Oliveri" <wuji@bigvalley.net> wrote in message
> news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> > I was talking to a guy regarding a 258 short block (he has two) and on
top
> > of the pistons is the number 58 stamped into them on both blocks.
> >
> > Would this be a .60 over bore or something different?
> >
> > Thanks,
> >
> > Bill
> >
> >
>
> It's possible, but that isn't standard practice. Maybe the engine shop
that
> rebuilt the engine measured the pistons and they were .058 oversize, which
> would be about right for a .060 overbore assuming .002 piston clearance.
The
> best way to know for sure is to have someone with the proper measuring
tools
> measure the bore diameter. For reference purposes you could even use a
dial
> caliper to check it and be within .001 or so, which would be acceptable.
The
> stock bore is 3.750 and .060 overbore would measure 3.810.
>
> Chris
>
>

 

I have a feeling that is some type of factory stamping, but someone like
Mike or Bill H. would know more about that than I would. I wouldn't think
that someone would intentionally bore an engine .060 over on it's first
rebuild, unless it was necessary. Most times .020 or .030 will do just fine
for the first overbore. Stranger things have happened though.

Chris


"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c59vnm$2pvg5f$1@ID-193866.news.uni-berlin.de...
> Thanks for the reply Chris,
>
> I thought it unusual for two blocks to have the same stamp on the pistons.
> Could this be a stock numerical representation? One of the blocks is an
84
> and one is an 85. He said the current one in the jeep (85) has been
driven
> not much in the last 10 years since he had it. If true that would make it
> going from stock to 60 over bore within 10 years. Possible but seems a
> little extreme doesn't it?
>
> Thanks,
>
> Bill
>
>
>
>
> "c" <c@me.org> wrote in message
> news:K4%dc.27016$YC5.14309@twister.rdc-kc.rr.com...
> >
> > "William Oliveri" <wuji@bigvalley.net> wrote in message
> > news:c59r74$2qk34j$1@ID-193866.news.uni-berlin.de...
> > > I was talking to a guy regarding a 258 short block (he has two) and on
> top
> > > of the pistons is the number 58 stamped into them on both blocks.
> > >
> > > Would this be a .60 over bore or something different?
> > >
> > > Thanks,
> > >
> > > Bill
> > >
> > >
> >
> > It's possible, but that isn't standard practice. Maybe the engine shop
> that
> > rebuilt the engine measured the pistons and they were .058 oversize,
which
> > would be about right for a .060 overbore assuming .002 piston clearance.
> The
> > best way to know for sure is to have someone with the proper measuring
> tools
> > measure the bore diameter. For reference purposes you could even use a
> dial
> > caliper to check it and be within .001 or so, which would be acceptable.
> The
> > stock bore is 3.750 and .060 overbore would measure 3.810.
> >
> > Chris
> >
> >
>
>