Author Topic: 1968 GT 390 (San Jose) Odd Engine block markings inside block  (Read 513 times)

Offline bullitt68

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Has anyone seen these markings inside the block before. My engine builder says they were drawn on at the factory to tell the line what pistons to put in the block. FYI this is an original bore block never messed with until now. Any help would be appreciated thanks
Mike
1968 Mustang Fastback GT 390 Raven Black, 4 speed
8R02S162374, San Jose, June 5, 1968

Offline carlite65

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #1 on: March 13, 2019, 10:07:54 PM »
pics would be nice....
5F09C331248

Offline bullitt68

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #2 on: March 13, 2019, 10:11:30 PM »
Sorry. Not sure why, but for some reason I am not able to upload the photos. Have been trying for a while on different devices and no luck so far
Mike
1968 Mustang Fastback GT 390 Raven Black, 4 speed
8R02S162374, San Jose, June 5, 1968

Offline bullitt68

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #3 on: March 13, 2019, 10:15:12 PM »
pics would be nice....

Looks like the photo just showed up mysteriously!
Mike
1968 Mustang Fastback GT 390 Raven Black, 4 speed
8R02S162374, San Jose, June 5, 1968

Offline 70cj428

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #4 on: March 13, 2019, 10:33:37 PM »
Not uncommon, I'm pretty certain the numbers correspond to bore size so they could select fit the pistons ....

John

Offline bullitt68

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #5 on: March 13, 2019, 10:42:31 PM »
Thanks John
Mike
1968 Mustang Fastback GT 390 Raven Black, 4 speed
8R02S162374, San Jose, June 5, 1968

Offline RoyceP

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #6 on: March 14, 2019, 09:56:49 AM »
Correct. The pistons were select fitted by the assembler. The bores were inspected after machining and marked so that all the assembler had to do was select the proper size piston / rod assembly to go in each hole.
 

Not uncommon, I'm pretty certain the numbers correspond to bore size so they could select fit the pistons ....

John
1968 W code 427 Cougar XR-7 GTE Feb 23 Dearborn C6 / 3.50 open
1968 R code 428CJ Cougar XR-7 May 13 Dearborn C6 / 3.91 T - Lock

Offline bullitt68

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Re: 1968 GT 390 (San Jose) Odd Engine block markings inside block
« Reply #7 on: March 14, 2019, 10:14:26 AM »
Correct. The pistons were select fitted by the assembler. The bores were inspected after machining and marked so that all the assembler had to do was select the proper size piston / rod assembly to go in each hole.

Thanks for confirming Royce
Mike
1968 Mustang Fastback GT 390 Raven Black, 4 speed
8R02S162374, San Jose, June 5, 1968