What makes a 5.7 280 HP vs 320?

[Nicad]

Being a car enthusiast for a long time I was wondering what the differences are in the various 5.7 litre engines that gives them different outputs? Compression, cam, software?? My 2001 226 has 280 HP. (I am paying for it Wednesday, so it's not mine yet) Does the 280 HP version need high octane fuel? Are the torque characteristics much different from the higher output models?
Thanks in advance.

[Big Block Power]

Most of it is camshafts. Yes software is different. Yes there is a difference you can feel I the seat of your pants. You will be ok in that boat though.

[Nicad]

Just noticed that it might be a 320 HP model. When I phoned Cobalt and gave them the VIN, they said it was 280 HP. When I looked at the original Texas registration it said 320HP. Is there a way to figure this out with a photograph of the engine?

[Skiingstrongman]

Is it Volvo or Merc?

[Nicad]

It's a Volvo

[Skiingstrongman]

Volvo usually has a plate that looks like this on it. Th

IMG_2495.JPG

at number is your HP.

[Big Block Power]

Yes take a picture of your engine cover for us. Also looking at the front of the engine and look down at the hoses going to the water pump and there will be tags on it. Or mine also had it on the power steering pump housing. Take a picture of that. You can't trust the title or even sometimes the engine covers. Some people have been known to switch them just to make more money when selling them.

[Bfun220]

You can't trust the title or even sometimes the engine covers. Some people have been known to switch them just to make more money when selling them.

You trying to tell me something ? Lol

[Big Block Power]

^Yea I should have put a 5.7gxi cover on yours and sold it for more I left money on the table.

[jhnmdahl]

Between the V8-225 and V8-300, the only difference appears to be the ECU. For the V8-320, they spec a different block, but I don't see any other obvious differences other than ECU again.

[Tuscany]

VVT on these engines?
That seems way too much of a power difference for an ECU to make up with simple fuel & timing.
I would bet that if you check pistons and cam, they would be different.

[jhnmdahl]

Tuscany, they appear to be the same from what I can see:

https://www.marinepartseurope.com/en/vo ... 03947.aspx

Makes it tempting to buy the ECU for a V8-300 and see what happens, or maybe reflash if that's an option.

[Nicad]

It says GX1 on the cover. I'll post a photo after I recharge my cell later today. Is that a 320hp ?
Certainly seems like a wild animal when I floor it.
Just went for a drive to the new property today.
Tricky boat to dock compared to my friends Larson All American.

[Ytmsn]

I always thought the hp difference was in the heads along with the program installed.

[Big Block Power]

Yes that's the 320hp. Guys on the new vvt I have no idea. I'm sure if it was as easy as swapping ecu there would be a bunch of guys doing it. But like John said I've seen this in other forms as well.