440 factory overbore?

• Mar 15, 2010

• #1

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texascharger73

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I have a 440 engine cast number 3698830.440.7. The bore measures 4.50 and not the 4.32. Is that possible form the factory? this motor has never been in a car and was used very little. When i took it down there is very little wear and from what I can tell it has never been touched.
Anyone know if they overbored them from the factory? There is no stamping by the distrubitor, just block casting number. Thanks for any help.

 

• Mar 15, 2010

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Meep-Meep

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Can't be 4.5". I think you mean 4.35". If so that would be .030" over, and while one or more lifter bores and crank journals came out of the factory over/under size, I never seen over sized pistons from the factory. Not to say it couldn't happen, but I've never seen it. Blocks with over sized lifter bores were marked with a diamond and .010" under journals had the Maltese cross.

 

• Mar 15, 2010

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godfatherofchry

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is this an industrial motor? I have seen factory over bores 20 30&40 in the big and small blocks..

 

• Mar 16, 2010

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texascharger73

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Thanks for the responses. You are correct I'm talking about 4.35. This motor was set on a irrigation well, so it is industrial. I double checked it yesterday and I also found 30 stamped on the pistons. Everything else seems stock, It has a double roller chain, stock rockers, springs and 346 heads. Is it normal for a industrial motor to not have any stampings on it?

 

• Mar 16, 2010

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I have a 1971 440 six pack, that is factory .020 over bore. there shoud be a letter A on the date pad. Mine has a HPA on the pad

 

• Mar 16, 2010

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696pack

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Yes, it was not uncommon to have not only factory overbored engines but also undersized rod and main bearings and oversized valve guides and stems. They have codes for all of this that when it happened it was stamped on the ID boss behind the water pump so that if a dealer had to do warranty work they would know what was in the engine before opening it up.

 

• Mar 21, 2010

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UrbanXX

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If you look on the distribtor boss where 440 is stamped you will see some numbers stamped there that will tell you if anything that was not standard on the block from the factory. I.E. undersize/oversize.