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08-03-2011, 03:35 PM #1
I have a later date of manufacture 260 with 280 block? Anything different?
The motor is in storage but if i remember correctly late 1997, like december or such date of manufacture. It is a 260 but the block has the bosses on the top for the alternator mount like the 280 uses. I'm no expert on these but seems like i remember the 260 exh ports in the cylinders were a little more aggresive (higher) than the 280, but the 280 got extra power from the exhaust chest of the block being hand ported??? I thought maybe someone here has some insight on this. I'm just curious. Thanks, Damon
1990 Viper 140 crossflow
2011 Sea Hunt 232 Ultra
1995 Laser 380
1984 Reaction 19 project.........
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08-03-2011, 05:14 PM #2
If it takes o-ring heads its a 280. Gasket heads its a 260.............
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08-03-2011, 05:32 PM #3
260..
It's definately a 260, the alternator bosses aren't tapped. I was just curious if the exhaust chest would be cast like the rest of the 280's since it's a 280ish block??? Or would it just be like a regular 260 block, it has the gasket heads since it's a 260.
1990 Viper 140 crossflow
2011 Sea Hunt 232 Ultra
1995 Laser 380
1984 Reaction 19 project.........
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08-03-2011, 06:02 PM #4
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08-03-2011, 08:17 PM #5
As far as I know 260 porting was different than 280's including the chest, not sure about the last year but thought 260 was a 260 and 280 was 280. Jay Smith should know for sure as he has seen way more than the average guy will see in a lifetime, if there was a oddball he should know.
Dave1980 Cougar 19 tunnel,90 2.4L Bridgeport EFI in middle of restoration.
1988 BAJA Sunsport 186, 96 225 Pro Max
79 12' Auminum, 95 Merc 9.9
RIP Stu
"So many idiots, so few bullets"
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08-04-2011, 08:49 AM #6
260..
i hope jay chimes in, i'm sure he knows.
1990 Viper 140 crossflow
2011 Sea Hunt 232 Ultra
1995 Laser 380
1984 Reaction 19 project.........
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08-04-2011, 09:05 AM #7Supporting Vendor
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There are a few late model 260 that indeed had the alt bosses but werent tapped. The chest on a 280 is like a drag with very little material left. This action killed bottom so Mercury lowered the port height to 1.600" on the other hand the 260 is full of material and they have a 1.565" port height.. The 260 port mapping can be higher that the 280 because the chest material creates torque . Drag is 1.535" with no chest like the 280 BUT relys on elevated compression to enhance lower end torque..
JayJay @ JSRE
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08-04-2011, 12:14 PM #8
260
thanks jay,
1990 Viper 140 crossflow
2011 Sea Hunt 232 Ultra
1995 Laser 380
1984 Reaction 19 project.........