OMC 3.0 block with 2.5 Head

wayne j

Cadet
Joined
Aug 22, 2010
Messages
10
Hi all, need someone with some boat experience to help get our new (to us) boat into the water. Purchased the boat with a "blown motor" turned out when I pulled the head that all of the exhaust valves were sunken into the head and the head gasket between cyls 2 and 3 was blown. Had the head repaired with hardend seats and got the gasket kit for the 3.0 ltr. When assembling we noticed the intake gasket does not seal correctly on ports 2 and 3. It appears that in a previous repair, we found the invoice in the paper work with the boat, the head had been replaced. When talking to my machinest he said it was a 2.5ltr head not a 3.0ltr head....
Any idea if I can use a 2.5 intake gasket with the 3.0ltr intake/exhaust manifold?? Hoping, especially now that we spent the money on the head work, that there is a way to make the intake seal, also alittle worried about coolant passages and oil passages in the head with the 3.0ltr head gasket. Can anyone give me any info? Thanks for your time.
 

fishrdan

Admiral
Joined
Jan 25, 2008
Messages
6,989
Re: OMC 3.0 block with 2.5 Head

I wouldn't worry about the head/block passages, but would be very concerned about the manifold to head ports matching. There are several head configurations for GM 4cyl marine engines...

marine-manifold-gaskets.jpg
 

bigdan1

Petty Officer 3rd Class
Joined
Aug 9, 2010
Messages
95
Re: OMC 3.0 block with 2.5 Head

personnaly what i would do.....
compare both heads on the bench .....

1) if they are similar : go for it .
2) if difference in port position : youll have to use the int/exh manifold that matches the head
 

wayne j

Cadet
Joined
Aug 22, 2010
Messages
10
Re: OMC 3.0 block with 2.5 Head

OK thanks for the quick help guys. From the pics my dad sent me ( both of us are automitive techs by trade) , I think I need the 17300. Are those Fel-Pro numbers then??
 
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