How to tell the difference between a 260 and 280 block/heads?

[951prerun]

I bought a motor and the seller said it was a 260 motor with 280 long block on it. How can you tell the difference between a 260 and 280 block/heads? I just want to know what I have. Thanks!

[albypine]

I bought a motor and the seller said it was a 260 motor with 280 long block on it. How can you tell the difference between a 260 and 280 block/heads? I just want to know what I have. Thanks!number's on the block.

[951prerun]

As in serial number?

[h2oskiier30]

Well...it's a little tricky. As albypine said, the only sure way is by running the serial number on the block.

The only sure thing is this: If the block does not have the cast in alternator bosses...then it is NOT a 280. ALL 280's had the alternator bosses cast in, and the last year of the 260's had them. So, if your block has the alternator bosses, it could be either...but if it doesn't have them, it cannot be a 280.

280 heads were all o-ring heads, and 260 heads were gasketed...from the factory. However, one can run gasketed heads on a 280 block by slotting the head bolt holes on the heads.

It sounds like your motor is most likely a 280 block with 260 electrics, but the only way to be sure is to run the serial number.

[samari]

along with what h2o said, 280's have the bosses tapped where a 260 isn't.

[h2oskiier30]

along with what h2o said, 280's have the bosses tapped where a 260 isn't.


:iagree: Also, it could be a drag block if the bosses aren't tapped.

[951prerun]

Thanks guys!

[patchesII]

Pull a head bolt if it has gasket heads. If the bolt hole in the head is slotted it's a 280. If not it's a 260 or a drag

[albypine]

if someone got grindder happy might want to check port timming to . some place is the measurements for 260/280/300 and thats done by measuring the hight of the port's in the boar. everyone gave easy way's to tell just by looking at it,but then you really need to see what's been done to everyting.Lot's of hacked up block's out there. And it's a shame because someday it will be hard to find one that has not been cut to death or over cut

[Jay Smith]

1. ALL 280 blocks are drilled an tapped for alternater
2. Stock 280 have O ringed heads
3. Stock 280 have flat seal cap on top
4. Exhaust port timing on 280 approx.1.625" from deck
5. 280 has no meat in the chest like drag
6. 280 block have wide and high transfer and boost ports
7. 280 stock nik/nicom bores 3.500 "

VERSES 260 which has:

1. Can have alternator bosses but aren't tapped
2. Stock 260 has gasket heads
3. Stock 260 has stator style top cap
4. Exhaust port timing higher ( 1.565" from deck )
5. 260 has chest full of "meat" ( metal )
6. 260 has lower and more narrow transfer and boost ports
7. 260 stock nik/nicom bore

Hope that will help you identify when all fails run the serial number. It located at split case area on port side at top of motor and will have an OD, OB,OG # etc along with numbers . Most motors also have a "made date" to the right of that serial number higher on the block ..

Jay

[rev.ronnie]

If it is a 260, it will be here if it is 1996 or older.

http://www.maxrules.com/models/Merc_model_files/HIPERF.html

[951prerun]

1. ALL 280 blocks are drilled an tapped for alternater
2. Stock 280 have O ringed heads
3. Stock 280 have flat seal cap on top
4. Exhaust port timing on 280 approx.1.625" from deck
5. 280 has no meat in the chest like drag
6. 280 block have wide and high transfer and boost ports
7. 280 stock nik/nicom bores 3.500 "

VERSES 260 which has:

1. Can have alternator bosses but aren't tapped
2. Stock 260 has gasket heads
3. Stock 260 has stator style top cap
4. Exhaust port timing higher ( 1.565" from deck )
5. 260 has chest full of "meat" ( metal )
6. 260 has lower and more narrow transfer and boost ports
7. 260 stock nik/nicom bore

Hope that will help you identify when all fails run the serial number. It located at split case area on port side at top of motor and will have an OD, OB,OG # etc along with numbers . Most motors also have a "made date" to the right of that serial number higher on the block ..

Jay


I know this is old but I still have no idea what power head I have. There is no serial no. to the left of the build date (really I looked everywhere). The build date is 5 6 04 (so is it possible to be a 260 and be so recently built?). However, there is a number stamped in at the bottom of the case split: 0462524 (or maybe C462524). The block has alternator bosses but they are not tapped. From the exterior the heads have gaskets but I will pull the heads this week and take a peak inside.

I am lost. Any thoughts?

[sxpilot]

with all that you have done to that daytona it looks like it came out nice, i would send that powerhead to Jay for his 4995 320+hp build...:D

[h2oskiier30]

I know this is old but I still have no idea what power head I have. There is no serial no. to the left of the build date (really I looked everywhere). The build date is 5 6 04 (so is it possible to be a 260 and be so recently built?). However, there is a number stamped in at the bottom of the case split: 0462524 (or maybe C462524). The block has alternator bosses but they are not tapped. From the exterior the heads have gaskets but I will pull the heads this week and take a peak inside.

I am lost. Any thoughts?

Definitely not a 280 if the alternator bosses are not drilled. Sounds like a replacement block from Merc...quite a few of them didn't have serial numbers. Narrows it down to either a 260 or drag. And yes, Merc did replacement 260 blocks in 04.

[patchesII]

Most likely a 260 if it has gasket heads. Only way I know to tell a 260 and Drag apart is to pull the exh divider plate that the coils are bolted to. If it's running good I wouldn't worry about it, just enjoy the motor. You can answer your questions when the motor comes apart for a re ring

[951prerun]

Thanks for the info.

SXPILOT, it's on the to-do list.......

[sxpilot]

Thanks for the info.

SXPILOT, it's on the to-do list.......

hey bro, im just sayin, I can hear it in your voice you want to be able to say man this thing has too much power...lol

Just a reliable every day 100 mph runner! I loved my daytona, fun a s s ride!