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

[Lakebagger]

Recently acquired a boat with a seized motor. Decided to go with a rebuilt longblock which I was told that I was receiving a gm mercruiser 7.4 gen v longblock which i know I have a 7.4 gen v after I verified it with the serial number on the block. What I received clearly shows a difference in the ports. Gen V has an additional port in the center of the head. The one I received doesn't have that port. I tried to post a picture, but it wont go through. It almost looks like they sent gen vi block with mpi heads which is a clear difference from my gen v setup that is carbed. I dont know For sure if it mpi, this is a lack of knowledge for me. I know for sure that my gen v intake manifold does not fit onto this gen vi engine. How much of a difference am i looking at to try to make this setup work with my boat? What are my options? How close is this gen vi engine to my gen v so that I can use my existing parts. Any advice is greatly appreciated.

 

[alldodge]

Welcome
Might have been set a 454 Mag which would have 502 heads
Look under the valve cover for last 3 numbers of 088 and 934

Gen VI 454 block has casting 12561357 or 10237297 (for L29)

 

[Scott Danforth]

You want a Gen VI vs the problematic Gen V

Oval port heads make it the L29. Rectangular port heads make it the 454 mag

 

[Fun Times]

What Mercruiser serial number/s do you have?

Mercruiser Block ID Codes – Big Block V8 Marine Engines | PerfProTech.com

The specific model/vintage of Big Block V8 Mercruiser Marine Engines can be determined by looking at the last letters of the engine code which is stamped by General Motors at the time of assembly on all complete Marine Longblocks . If the serial number and/or model decals are missing, the Marine...

www.perfprotech.com

 

[Lakebagger]

Welcome
Might have been set a 454 Mag which would have 502 heads
Look under the valve cover for last 3 numbers of 088 and 934

Gen VI 454 block has casting 12561357 or 10237297 (for L29)

Looks like a 454 VI block casting number 10237297. What does it entail to use this engine with parts from my gen V? How many different parts will I need to purchase that are not compatible between the engines? I like the idea of the gen vi, but not if I have to dump a bunch more money to get it to work

 

[Lakebagger]

What Mercruiser serial number/s do you have?

Mercruiser Block ID Codes – Big Block V8 Marine Engines | PerfProTech.com

The specific model/vintage of Big Block V8 Mercruiser Marine Engines can be determined by looking at the last letters of the engine code which is stamped by General Motors at the time of assembly on all complete Marine Longblocks . If the serial number and/or model decals are missing, the Marine...

www.perfprotech.com

F012397

 

[Lakebagger]

You want a Gen VI vs the problematic Gen V

Oval port heads make it the L29. Rectangular port heads make it the 454 mag

They are oval ports. Does the gen vi have a intake manfold for a carb setup? This is all new to me so pardon the stupid questions.

 

[alldodge]

Will need new intake (rectangular port), probably re-jet current carb

Yes they make carb intake for Gen VI rectangular ports

 

[alldodge]

Looks like you might also need a different flywheel, unless your current is 454 Mag

Your serial number list 2 different flywheels
Gen V 7.4 used 811562T
Gen V 454 Mag used 843374T1

Gen VI 502 used 843374T1

 

[Fun Times]

F012397

0F012397 = 1993 MERCRUISER TB4, W/PS, TWOPCEX, WORO, GEN-V 7.4L BRAVO model number 474B1103S.

This serial number is for the 7.4, not a 454 Mag.

454 MAG. BRAVO (GEN. V) GM 454 V-8 1992-1994 - 0D805069 THRU 0F304999

454 MAG. BRAVO (GEN. V) GM 454 V-8 1992-1994 - 0D805069 THRU 0F304999

www.mercruiserparts.com

 

[Lakebagger]

Looks like you might also need a different flywheel, unless your current is 454 Mag

Your serial number list 2 different flywheels
Gen V 7.4 used 811562T
Gen V 454 Mag used 843374T1

Gen VI 502 used 843374T1

I definitely do not have a gen v mag 454. So does everything belt driven up front, fuel pump, power steering all bolt up fine? I'm having a hard time searching for a gen vi intake that takes a carb. Im trying to price everything out

 

[Lakebagger]

0F012397 = 1993 MERCRUISER TB4, W/PS, TWOPCEX, WORO, GEN-V 7.4L BRAVO model number 474B1103S.

This serial number is for the 7.4, not a 454 Mag.

454 MAG. BRAVO (GEN. V) GM 454 V-8 1992-1994 - 0D805069 THRU 0F304999

454 MAG. BRAVO (GEN. V) GM 454 V-8 1992-1994 - 0D805069 THRU 0F304999

www.mercruiserparts.com

That's what I came up with too. I tried posting a photo but getting error " the upload failed because the file could not be written to the server...." I tried resizing it, but no luck. Is there something I'm missing to attach a photo?

 

[Scott Danforth]

Gen V used peanut port heads. Gen VI head is a true vortec head. Can use most BBC oval port intakes

We are having server issues preventing posting pictures. We have reached out to the hosting admin folks

 

[alldodge]

CP Performance

Mich Motorz

Search for 502 marine intake rectangular port, it will also bring up oval but have to look close

iBoats has pic upload problems and MODs are working on it. I/we hope to be able to put something out more about it soon

 

[Fun Times]

That's what I came up with too. I tried posting a photo but getting error " the upload failed because the file could not be written to the server...." I tried resizing it, but no luck. Is there something I'm missing to attach a photo?

It’s on the forum side issue wise and we’re unsure of a repair date…The only way to share photos right now is to link an outside photo hosting website.

 

[Scott Danforth]

Since this is a basically a new install. I would suggest adding a heat exchanger

 

[Lakebagger]

Since this is a basically a new install. I would suggest adding a heat exchanger

I read about this in another thread. The boat has about 500 total hours. The exchanger seems to be pretty penny, could you elaborate on the benefits of a new exchanger and life span. To be up front, this is my first boat. I got an incredible deal and, I've always been a boater at heart, but always on friends boats. I know they are expensive to maintain, which is why I'm trying to scoop up as much knowledge as possible. Do you know if there is any other suggestions on parts that may not match up between the gev v and vi?

 

[alldodge]

I'll let @Scott Danforth get into the HX, but we could use what boat do you have and are you in fresh or salt water?

Going to a 454 Mag with 502 heads means you could go with a full 502 and pick up another 80 hp or so. The 502 would mount up to the 454/7.4 without issues

 

[Lakebagger]

I'll let @Scott Danforth get into the HX, but we could use what boat do you have and are you in fresh or salt water?

Going to a 454 Mag with 502 heads means you could go with a full 502 and pick up another 80 hp or so. The 502 would mount up to the 454/7.4 without issues

Fresh water in utah. It's a 93 crownline 225ccr

My only options are to make this rebuilt 7.4 gen vi work or return it to get the 7.4 gen v that I orginally ordered. At this point I'm not looking to go any more gas guzzling. Not needing more power, I think. Just get the boat on the water before Oct.

 

[Scott Danforth]

A heat exchanger means the motor has ethylene glycol running thru it vs raw lake water.

From a winterizing point of view, much easier. From an operational temperature point of view, less engine wear, better efficiency

Your old motor was frozen up for a reason.