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Discussion Starter #1
I sold my 250,000 miles block due to too much ridge and bought another one with 150,000 miles. After stone honing and flex honing, here are my number below. I used a digital dial bore gauge and took 3 reading 1" from the top and another set of reading toward the bottom.

The number 7 needed extra hone due to little rust spots which is why its the largest.

This 5.0 is going in my 64 Falcon with maybe the E303 or TFS Stage 1 cam. I will not be racing but just cruising with a T5. May even put the Explorer Cam back in.

Should I still have the block bored 0.030 over?

Number 7 concerns me. It has no taper but the bore is 4.003"

#1
4.0024 / 4.0020 / 4.0020
4.0024 / 4.0024 / 4.0020

#2
4.0024 / 4.0020 / 4.0020
4.0024 / 4.0028 / 4.0020

#3
4.0028 / 4.0020 / 4.0016
4.0016 / 4.0020 / 4.0012

#4
4.0028 / 4.0028 / 4.0016
4.0020 / 4.0024 / 4.0012

#5
4.0020 / 4.0020 / 4.0008
4.0012 / 4.0012 / 4.0004

#6
4.0008 / 4.0012 / 4.0008
4.0004 / 4.0012 / 4.0004

#7
4.0031 / 4.0031 / 4.0031
4.0031 / 4.0031 / 4.0031

#8
4.0020 / 4.0008 / 4.0016
4.0012 / 4.0008 / 4.0008

Thanks

Waid
 

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5.0L HO (GT and Cobra)
Cylnder bore diameter 4.000-4.0048
Out of round limit 0.0015
Out of round service limit 0.005
Taper service limit 0.010

A 4.003 is within spec but its cutting it close. A 4.0048 is the as much as the factory rings can handle. You can bore to .010" or .020" or .030". A .010" should be all you need if all it will be is a cruiser. If you want to go .030" then go for it, but no larger.
 

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^ if that broad of tolerance would make you happy, then you could buy an engine anywhere. Im sure you got those specs from a manual somewhere, but remember, an engine going in the family minivan vs an engine going in a performance application, the specs are way different.
To the op, no determination can be made till you post up each piston diameter, measured with piston upside down, .5" down from the bottom of the skirt. That will give you piston diameter.
Also, how are you arriving at .0001" measurements with a .001" gauge?
 

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Discussion Starter #4
nxcoupe, I replaced the analog dial indicator with a digital in my dial bore gauge. My digital dial indicator only reads +0.0005" / -0.0005 and displays nothing in between so I swiched to metric mode 0.00mm in order to get better resolution. Therefore the resolution is metric is +0.01/-0.01mm which is 0.0003". So all of the readings that I took were in metric and convert it back to standard.



To the op, no determination can be made till you post up each piston diameter, measured with piston upside down, .5" down from the bottom of the skirt. That will give you piston diameter.
I will measure the piston diameters tonight and post some numbers.

Thanks
 

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Ok, after contemplating this, i want to make a suggestion. Measure each bore from outside most point to lifter valley side most, in three places. Top (.5" down from top), middle, and bottom (about .25" up from bottom). Post those and you will give me a much more accurate picture of whats going on with it.
 

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Discussion Starter #6
nxcoupe, here are my pistons:

#1: 3.9981
#2: 3.9973
#3: 3.9971
#4: 3.9982
#5: 3.9985
#6: 3.9982
#7: 3.9981
#8: 3.9985

Please note that Explorers came with Hypereutectic Pistons from factory.

Explorer Service Book:

Pistons: 3.9987-3.9993
Cylinder Bore: 4.0000-4.0012
Cylinder Bore Out-of-round and taper: 0.0015 / 0.010
Cylinder Bore to piston clearance: 0.0012-0.0020

Waid
 
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