swap 2.5 omc for 3.0 merc

[Phantom17]

I have a 1981 omc GM 2.5 in good shape. I want to put it into a stingray with an 85 GM merc 3.0. Is this the same block? I know I need to change over exhaust / intake, muonts etc, but will the block line up with all the right holes in all the right places? Just making sure. Thanks

 

[Laddies]

Re: swap 2.5 omc for 3.0 merc

Even though the blocks are differant every thing will interchange the carb may need to be rejetted

 

[Phantom17]

Re: swap 2.5 omc for 3.0 merc

the blocka are different?!?!?!?! I've been told they're the same, and I'd need to change the manifolds, because those are not. Enlighten me, please!

 

[Phantom17]

Re: swap 2.5 omc for 3.0 merc

I will be using the 2.5 block, and the carb, intake / exhaust, riser etc from the 3.0........... just to be clear.

 

[Laddies]

Re: swap 2.5 omc for 3.0 merc

The 2.5 is 153 cu.in and the 3.0 is 181 cu.in a larger bore the 2.5 has no harmonic balancer and is internal balanced and the 3.0 has harmonic balancer other than that they are the same block on the outside

 

[Bondo]

Re: swap 2.5 omc for 3.0 merc

Ayuh,........<br /><br />If you're talking about putting a 2.5l OMC , GM block in place of a 3.0l Mercruiser, GM block ,......<br />No Problem,..... All the Holes are Right where they Belong,.............<br /><br />Any other GM 2.5l motors are Totally Different..............

 

[Phantom17]

Re: swap 2.5 omc for 3.0 merc

Thanks bondo, btw, you mentioned the epoxy on the 3.0, know of/ heard of any good places in the Boston area?