Pretty sure I was sent Gen VI, not Gen V 454

[Lakebagger]

I feel like this new motor I have is a 7.4 MPI gen VI vs my 7.4 gen V. The heads seem to be different, look looks the same. Looking at parts diagram, the 7.4 gen V and the 7.4 gen VI look very similar, but when I look at a parts diagram of a 7.4 MPI Gen VI looks quite different which aligns closer to the heads I have. Maybe not. This making any sense?

 

[alldodge]

Just for visual only, this is oval port top, rectangular port on bottom

 

[Lakebagger]

Just for visual only, this is oval port top, rectangular port on bottom

Top is the current one I have on my gen v

Here is a picture of the new motor i currently have

20240809-095135 hosted at ImgBB

Image 20240809-095135 hosted in ImgBB

ibb.co

Old motor I have

20240809-100903 hosted at ImgBB

Image 20240809-100903 hosted in ImgBB

ibb.co

 

[alldodge]

They have the same heads
so you have a Gen VI block but original oval heads

Should be same HP, only issue is attaching hardware holes. For the most part your good

EDIT:
wait scratch that you don't have water/exhaust flow thru port in center

 

[alldodge]

pics old

New

 

[Lakebagger]

They have the same heads
so you have a Gen VI block but original oval heads

Should be same HP, only issue is attaching hardware holes. For the most part your good

EDIT:
wait scratch that you don't have water/exhaust flow thru port in center

Yeah that's my concern. Nearly everything else looks similar except the timing cover

 

[alldodge]

Yeah that's my concern. Nearly everything else looks similar except the timing cover

The cover should be no issue from my perspective. Seems to be same plane

 

[Lakebagger]

The cover should be no issue from my perspective. Seems to be same plane

The cover interferes with the bottom side on the gen v intake manfold. There is a half inch clearance issue. Might just end up sending this back and hopefully they send me the right one. It's been a more than an unpleasant experience trying to even get the engine in the first place. Appreciate the feedback from you though.

 

[alldodge]

The cover interferes with the bottom side on the gen v intake manfold. There is a half inch clearance issue.

Hey @Scott Danforth ???

 

[Fun Times]

It appears you have Merc part number 938-8M0115141,

https://www.mercruiserparts.com/mercury-mercruiser-938-8m0115141-cyl-head-complete

Here’s a list of head fitment for I’ll assume all mercs without studying the list, etc.… yours is about the fifth one up up from the bottom,

https://www.mercruiserparts.com/cylinder-heads-2

 

[Scott Danforth]

Yeah that's my concern. Nearly everything else looks similar except the timing cover

Gen V timing cover and Gen VI only differ by number of bolts

Gen V has 10 bolts Gen VI has 6

Your boat doesn't have an EGR, so the EGR port in the head never comes into play. Gen V head do not have EGR ports.

Gen V heads only fit Gen V blocks. Gen VI blocks will take all Gen VI heads, and all Mark IV heads

The Gen V motors were half and half flat tappet and roller motors. All Gen VI motors are roller cams

You may have a Truck manifold for a flat tappet motor with the EGR cross-over cover under it. Just get an aftermarket BBC marine intake (dual alloy casting)

 

[Lakebagger]

Gen V timing cover and Gen VI only differ by number of bolts

Gen V has 10 bolts Gen VI has 6

Your boat doesn't have an EGR, so the EGR port in the head never comes into play. Gen V head do not have EGR ports.

Gen V heads only fit Gen V blocks. Gen VI blocks will take all Gen VI heads, and all Mark IV heads

The Gen V motors were half and half flat tappet and roller motors. All Gen VI motors are roller cams

You may have a Truck manifold for a flat tappet motor with the EGR cross-over cover under it. Just get an aftermarket BBC marine intake (dual alloy casting)

Thank you for all this info. I'm assuming everything off my gen v should bolt up to the gen vi, carb, water pump, power steering, linkage, hoses etc...?

 

[alldodge]

yes