390 Ribbed block
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Joined: Jun 1999
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From: Creedmoor, North Carolina
John
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Joined: Oct 2004
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From: Central Oregon
I have not seen a 390 with the ribs, But all the 360's that I have had in the past, did have them. I'm NOT saying that all 360's did, just the one's that I had. On some of those 360's we turned into 390's, so they had the stoke of a 390, but started out life as a 360.
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From: CT
Ribbed block is a 71 or later FE block that has vertical ribs going down both sides. Both DIF "352" and MCC reverse "105" blocks can have them. Reason is two fold, first to help support aging molds as blocks were cast or to give more structure strength to the block itself. No one really seems to know the exact reason. There were some non ribbed blocks late in production (75-76) so who knows?? LOL
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Don't know if it applies to cast iron blocks, but ribs and such are normally used in castings to allow for better fill of critical areas during the pouring process. You'll see them as well as cross hatch patterns on intakes and pistons too.
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Needsmorecoffee.
Joined: Oct 2004
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From: CT
Well there are exceptions to everything and the FE engine is a perfect example. 
There have been 427 and 428 blocks as early as 68 with ribs on them. But they consistantly weren't there till 71 and later.
There have been 427 and 428 blocks as early as 68 with ribs on them. But they consistantly weren't there till 71 and later.
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Joined: Jun 2003
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From: Allentown, PA
Actually I don't know. It's in a 69 stang but a previous owner transplanted the 390 in there. Origional motor was a 302.
I'm going to have to go back and look at some pics when the motor was out of the car to see if it has ribs. I can't see much of the side of the motor at all in that tiny engine compartment.
I'm going to have to go back and look at some pics when the motor was out of the car to see if it has ribs. I can't see much of the side of the motor at all in that tiny engine compartment.
Needsmorecoffee.
Joined: Oct 2004
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From: CT
Glad to help.