Head ID

[love1u0]

I picked up a new manifold according to my 3.0 serial# and it doesnt line up right. Doing a little research on the web it looks like my head is from a 2.5ltr.

Can anyone confirm or dispel this from the pictures, as I cannot locate a casting number on the head.

Pic I found on the web:

 

[Bondo]

Re: Head ID

Ayuh,... By the pictures, it appears you're Right....

Put it together,... It'll run Just Fine....

 

[love1u0]

Re: Head ID

Well, thats the problem. I have gone through two gaskets that match the new manifold and they both leak. I will attempt to get a gasket that matches the head. But Im not sure if I need to scrap the whole thing and buy a manifold for a 2.5ltr.

Is the head stock or did somebody have issues, and they replaced it with a 2.5ltr head?

 

[zbnutcase]

Re: Head ID

Couple of years ago I replaced a freeze cracked 3.0L from a late 80s Cobra and it too had the 2.5 style head. And as the customer bought boat new, engine had to leave GM factory that way. 'nutcase

 

[Howard Sterndrive]

Re: Head ID

maybe put some grease on one surface, slide them together and then look at the pattern and see if a 2.5 gasket will solve it.

 

[Bondo]

Re: Head ID

as I cannot locate a casting number on the head.
I will attempt to get a gasket that matches the head.

Ayuh,.... The Casting # should be on the top, under the rockers...

Yes, get a gasket that matches the Head....

Before you bolt it back together,....
Check Both surfaces with a straight-edge....
I'm not sure the Spec, but there should be little to No deviations from Dead Flat.....

 

[love1u0]

Re: Head ID

Well I just got back from the marine shop and picked I up a gasket for a 2.5ltr and it matches the head perfectly, part#18-2896 replaces Merc/OMC #27-52546/311068.

Im guessing the head is not stock...am I losing performance with this head?

That is the first thing I did after the first gasket leaked Bond-o, thanks
for the suggestion.

 

[Bondo]

Re: Head ID

Im guessing the head is not stock...am I losing performance with this head?

Donno,... It might be 1 of the Better... Exhaust ports look Good...
It'd depend on combustion chamber volume,+ valve sizes....

Seems the exhaust manifold would be the Choke point of flow...

 

[zbnutcase]

Re: Head ID

You are losing performance. The late 8-port head is vastly superior to any of the early heads. Worth the swap? Would be if you could get an aftermarket manifold for it..Mercury only at this point...$ 'nutcase