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View Full Version : 2.5L and 2.5L HP-WHATS THE DIFFERENCE??


twig
05-30-2007, 11:51 PM
I'm wondering what the structural differences are beteen the standard Merc 2.5L block and the HP version?

Can a standard 2.5 be turned into a 260?

Thanks.
twig
06-01-2007, 04:17 PM
Someone must know??
wheeliejones
06-01-2007, 05:05 PM
Yes it can,

Just have your 2.5 block ported to the 260 or 280 specs and then all the electronics you would have to buy. Or pump up the carbs!
But I would wait to hear what Jay has to say. Ask Jay Smith...
tlwjkw
06-01-2007, 05:06 PM
Here's just a little bit: Just tha non movin' parts on tha block half
clyinders (Nic.)
ports
rod slots
exhaust
exhaust divider
heads (can be interchanged with post '91 V6 heads)

Yes it can. Ruck says "if you got tha money I got tha time"
twig
06-01-2007, 05:14 PM
Someone told me that the HP blocks are 4 bolt main and the standard type block are only 2??
tlwjkw
06-01-2007, 05:26 PM
First ones(early '90's) were two bolt, went ta tha four bolt a little later. Maybe '97 or '98 not real sure 'bout that. Same year they went to tha big ball type bearing on tha top I think..........
wheeliejones
06-01-2007, 05:27 PM
I think it was 1995 wasn't it?
tlwjkw
06-01-2007, 05:45 PM
Coulda been. I'm strechin' my old, burn't up cells just ta remember that much............
vectordriver
06-01-2007, 05:48 PM
Yes it can. Ruck says "if you got tha money I got tha time"


exactly, and ruck is THE man for anything with a merc!


the fishing motor blocks can be turned into pretty much anything the hp ones can be. just better pistons and rods and obviously the porting and efi system as well(the laser efi can make some serious hp too with some changes)..
tlwjkw
06-01-2007, 05:59 PM
We gotcha fixed up now huh, Twig

Later.....................T
twig
06-01-2007, 06:34 PM
I have just built a customer engine for ski racing in a stock production were the engines must be under 2.5 and not from the Merc racing.I went for a 1991 2.5 for the 7 pedal front.Once I pulled the powerhead down I found that its heavly ported and that it also has Hp mid section and sandwich plate.Not a big deal,found another block and the gear I needed to bring it back to stock for minimal outlay.But in the meantime I have some gear left over and wondering what fun I could have with it.

I wonder what the limits are for the two bolt main?
tlwjkw
06-01-2007, 06:37 PM
Same as 4 bolt...........
twig
06-01-2007, 07:47 PM
Are there any mods you can do to imporove a 2 bolt blocks life span??

Surley they can't be a stable as the 4.