427 truck block oil pressure fitting

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engineman1642
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427 truck block oil pressure fitting

Post by engineman1642 » Tue Aug 08, 2017 3:29 pm

I have a customer who has a 427 chevy truck block ,sez fitting above oil filter is neither 1/4 or 3/8 pipe.Anyone know what it might be? thanks

machinedave
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Re: 427 truck block oil pressure fitting

Post by machinedave » Tue Aug 08, 2017 3:51 pm

I have one in the shop now. I just checked it and it is 3/8" pipe.

SupStk
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Re: 427 truck block oil pressure fitting

Post by SupStk » Tue Aug 08, 2017 4:43 pm

+1
Also have one here and its 3/8 pipe.
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Newold1
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Re: 427 truck block oil pressure fitting

Post by Newold1 » Tue Aug 08, 2017 6:27 pm

The 427 tall deck truck block I have in my shop is also a 3/8"npt size threaded hole above the oil filter pad as shown above.
someone may have taped it out to a larger size like a 1/2" pipe or #10AN size. Seen this done many times for a remote oil filter or cooler setup.

engineman1642
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Re: 427 truck block oil pressure fitting

Post by engineman1642 » Tue Aug 08, 2017 7:45 pm

have not seen the block ,but he said that 1/4 " fitting falls into thread and 3/8" is way bigger than the thread in block.

SupStk
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Re: 427 truck block oil pressure fitting

Post by SupStk » Tue Aug 08, 2017 11:10 pm

Guess I've never seen the oil port above the filter in a BBC that wasn't at least 3/8 NPT. There are blocks that are even bigger but not in truck engines, from what I've seen.
Wonder if there is something, such as a reducer, adaptor or some other fitting screwed in the hole?
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gramps
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Re: 427 truck block oil pressure fitting

Post by gramps » Fri Aug 11, 2017 8:12 am

Had same deal SBC bowtie block lower water drains, ended up being 9/16-18 thread or AN6 plug.

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Re: 427 truck block oil pressure fitting

Post by pamotorman » Fri Aug 11, 2017 9:11 am

I have gotten used SBC blocks with 3/8 NTP plugs in the water jacket drains. most like the original 1/4 NTP threads were stripped,distroyed or rusted out.

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