LennyBoat

Hi All,

I am rebuilding a 454 PCM engine with a cracked block due to frost damage and I was directed here by one of the members of correctcraftfan (a forum for older ski boats).

Ideally, i would replace the engine core with an identical one, but in Europe these blocks are very hard to find.

The one I was able to find is a GEN V instead of the GEN IV I have. The work needed on this block is quite extensive so I want to make sure that this is possible before investing the money.

Some information about the original engine:

-GEN IV LH rotation

-GM hi-perf 14086188 heads

-4 bolt

-Forged pistons

-Edelbrock performer intake


The new engine is a GEN V Mercruiser, LH, 4 bolt, cast piston engine.


I know that the sump, crank, and timing chain cover are different, but I have all these parts except for the cover.

I would need to add an electric fuel pump as well I heard.


Is there anyone who has done a swap like this before?

Any help on this topic is greatly appreciated!


Cheers,

Lenny

Smitty275

You'll need matching flywheel and harmonic balancer. The camshafts are different and need a different timing chain set. There is a special head gasket for putting Gen IV headed on a Gen V.

f_inscreenname

You will have t use electric fuel pump.

BillK

Which head are you going to use ? Your 188 heads might not work depending on the GenV block. They can leak water into the intake manifold area. Some people claim they will work with a special gasket but I have seen 2 cases where they simply would not work.

If you have the entire GenV engine and plan on using the heads from it than you should not have any issues other than the flywheel.

LennyBoat

Thank you all for the information!
I only have the GEN V engine core, crank and cams.
I'ts starting to look that i'm better of buying a new engine core from summit and import it.
The cost of getting this block cleaned up is almost the same as a new block, adding the adaptations, I might come out around the same price.

f_inscreenname

Don't get me wrong, I love the Gen V. Most would pass them by because of "the stories" and I used to pick them up pretty cheap, not so much anymore. They are an upgrade to the Mark IV. Not as good as the Gen VI but they all had 4 bolt mains, one piece rear seal, better oil pan seal, better oil passages, etc, but GM just didnt commit to roller lifters and cam and some of the Mark IV stuff like heads didnt cross over so performance folks dropped off. They also used an electric fuel systems on all production motors so they didnt bother to cast in a mechanical fuel pump boss into the block which made even more people not like them. Things that were "fixed" in the Gen IV.

LennyBoat

I think I found a suitable GEN IV block, only difference is the casting number: 361959 instead of 14015445.
If I look these up it says "73-"90 and "78-"90 respectively.
Is there a large difference between these two?
My original is a 4-bolt, the replacement would be a 2 bolt. engine has 330 HP, so I don't think that will be an issue.

Tartilla

The Gen V oil pans fit on the Gen VI blocks though?

The Gen VI oil pan gaskets...are they just an upgrade and can be used on the Gen V?
​​​​
I have 2 frost cracked Gen V blocks...I want to replace them with Gen VI for the roller cam option, and the upgrades.

My 088 heads and cranks will work on the Gen VI...but now I'm not sure the oil pan will fit.

Sporl Performance

iTrader: (1)

I have gen 4 blocks.
Ron Sporl
504-616-6005

Tartilla

Thank you...it would be easier to run the Gen 4s...but I'm committed on the 1 pcs rear main at the moment.

At least for the forged cranks and 088 heads that don't like to play on the gen 4s.