Heads for 1997 7.4L Mercruiser Vdrive for my Searay 330 SD.

[Michael K Kibler]

I hired a mechanic to fix my backfiring 7.4L starboard engine, left with the heads and $ 2,500 for replacement parts and disappeared. I now need to replace the heads as a minimum and do not have any S/N for them. Is there a way to determine the correct heads without having the originals? I have looked on Ebay and a 99 MerCruiser 7.4 L 454 MPI V8 looks correct just from a visual standpoint/ports.

 

[John E3]

Hi, I had to replace the heads on a 1999 Mag MPI Horizon 7.4 (Gen 6) in my 370AC and found new heads that are a drop in replacement.
I got them from Crate Engine Depot. Part number 12562920 with casting number 12562925, matching the original 14097088 pretty much identically. The CRITICAL points are that they have rectangular intake ports, and 7/16" threaded holes on the ends for the brackets.
Check the intake to see if it's got the rectangular ports, and if you have 7/16 bolts.

I have about 20 hours on them, and they are working as expected.

Here's my saga - https://clubsearay.com/index.php?threads/potential-engine-pull-out.113033/post-1407729

One additional point - Use MARINE gaskets. Automotive gaskets are not the same. There are blocked ports and such which are very different.

 

[scoflaw]

Probably the L29 oval port heads unless it says magnum on the plenum.

 

[Scott215]

If you check the lifters. Make sure they go back in the same spot they came from unless they are roller lifters

 

[John E3]

If you check the lifters. Make sure they go back in the same spot they came from unless they are roller lifters

This is contrary to -everything- I read on this. Same for pushrods. I did have 2 rockers with excessive wear on the valve stem end, and replaced only those 2.
Experience may dictate otherwise....

 

[John E3]

Probably the L29 oval port heads unless it says magnum on the plenum.

Mine says Horizon.

 

[scoflaw]

Like mentioned look at your intake manifold to see if it's square port or oval or post up a picture of the ports

 

[Michael K Kibler]

Hi, I had to replace the heads on a 1999 Mag MPI Horizon 7.4 (Gen 6) in my 370AC and found new heads that are a drop in replacement.
I got them from Crate Engine Depot. Part number 12562920 with casting number 12562925, matching the original 14097088 pretty much identically. The CRITICAL points are that they have rectangular intake ports, and 7/16" threaded holes on the ends for the brackets.
Check the intake to see if it's got the rectangular ports, and if you have 7/16 bolts.

I have about 20 hours on them, and they are working as expected.

Here's my saga - https://clubsearay.com/index.php?threads/potential-engine-pull-out.113033/post-1407729

One additional point - Use MARINE gaskets. Automotive gaskets are not the same. There are blocked ports and such which are very different.

Hi John, I will check that today, I do have a pic of the intake gasket attached.

 

[John E3]

That's an exhaust gasket.

 

[Scott215]

Picture of the intake manifold would help

 

[Michael K Kibler]

Hi John, I will check that today, I do have a pic of the intake gasket attached. View attachment 153066

 

[Scott215]

Looks like rectangle port to me scoflaw what you think

 

[scoflaw]

Yes indeed

 

[John E3]

Yep, that's what mine looked like. Numbers above should apply.
Since it's apart find the merc code, belt end of block, left side (facing it) near top is a machined spot with a 2 letter code. The service manual is readily available by searching "mercruiser service manual 23" and those codes are on page 3A-16.

 

[blaster]

How about this “mechanic” who stole your cash and the heads. Was he a meth addict? I’d spend five times what I lost to hunt his ass down. To hell with cutting losses that’s really personal.

 

[Michael K Kibler]

How about this “mechanic” who stole your cash and the heads. Was he a meth addict? I’d spend five times what I lost to hunt his ass down. To hell with cutting losses that’s really personal.

Started out good, but ended bad, meth, maybe. I am trying to hunt him down.

 

[Michael K Kibler]

Yep, that's what mine looked like. Numbers above should apply.
Since it's apart find the merc code, belt end of block, left side (facing it) near top is a machined spot with a 2 letter code. The service manual is readily available by searching "mercruiser service manual 23" and those codes are on page 3A-16.

thanks John, that really helps.

 

[Flyer5]

How about this “mechanic” who stole your cash and the heads. Was he a meth addict? I’d spend five times what I lost to hunt his ass down. To hell with cutting losses that’s really personal.

No kidding. Tonya Harding his ass.

 

[Scott215]

Manhunt

 

[Michael K Kibler]

Hi, I had to replace the heads on a 1999 Mag MPI Horizon 7.4 (Gen 6) in my 370AC and found new heads that are a drop in replacement.
I got them from Crate Engine Depot. Part number 12562920 with casting number 12562925, matching the original 14097088 pretty much identically. The CRITICAL points are that they have rectangular intake ports, and 7/16" threaded holes on the ends for the brackets.
Check the intake to see if it's got the rectangular ports, and if you have 7/16 bolts.

I have about 20 hours on them, and they are working as expected.

Here's my saga - https://clubsearay.com/index.php?threads/potential-engine-pull-out.113033/post-1407729

One additional point - Use MARINE gaskets. Automotive gaskets are not the same. There are blocked ports and such which are very different.