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Discussion Starter #1
So Im a bit of a pirate, young and think I know everything but clearly no f all... I brought a boat with the intention of cruising the pacific ocean before the end of summer (I live in new zealand) but once I started looking at the overheating 454 in my boat my dreams have slowly been shattered.

1983 SEARAY SUNDANCER:
Mark V engine
Block number: 10114182
Head number: 10114156 gm5

I took the heads, block, crank and bits to the engine reconditioners and they called me today to say there is a crack in the head.....
Now I'm looking for second hand heads in new zealand but am having trouble because there are many 454 heads available but I'm not sure what will and what won't work.

My question is what heads can I use on my gen V 454?

Some people have said that I should use other heads to gain power which would be great but I have never had the boat in the water to know if I need more power...

the boat is 31 foot long and 10 foot wide weighing around 3 tonne so she isn't built for zipping around. I just want the damn thing in the water going forwards and back and i want it to be reliable but at the same time I don't want to rebuild the entire motor and it turns out to be a huge slug.

Any help would be greatly appreciated guys
 

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First! Marine applications are severe duty.
Nothing but the best parts should be used if adventures far from shore are expected. No used mismatched junk. If the engine is in question,take it out and completely take it apart and repair or replace everything that is in question,,,no short cuts,no inferior parts. Do a complete blue print of the engine.
 

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Discussion Starter #3
yea Im not a fan of cheap craps o i am using decent quality parts. that is whats happened, I pulled the engine out, stripped it back to a bare block and took it to the reconditioners. They called today to say that a head was cracked so I'm guessing that a the reason my bores were buggered from water sitting in them. the risers were also pretty stuffed so they are being replaced too. the block is getting honed and skimmed but now the problem is finding the right heads.
 

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not "decent" parts,you need the best.I would completely check every single part in the engine. Complete blue print of engine including balance. Im guessing now that the engine is torn down you want everything to match perfectly? If it has a flat tappet cam,toss that out.You may have to upgrade entire valve train.

do you have the casting numbers off the cracked heads?
 

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Discussion Starter #5
Mark V engine block number - 10114182

Head casting number - 10114156

well thats the plan, I have all new water pump, risers, oil pump, sensors and a few other bits so far. Every bolt used will be brand new ARP stainless bolts and clearly new rings, pistons, gaskets and bearings and so on.

how would I upgrade that side of things?

If i got any heads that aren't new I would get them reconditioned before they even went near the motor. I just don't want to be pulling it out in 12 months time coz of a stupid rookie mistake or from a failure from using cheap chineese parts (which I am not doing). If it was a car i probably wouldn't care as much but the last thing I need in the middle of the ocean is a mechanical failure
 

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If it's got a stern drive, make sure it's worth fixing. All the OMC's of that era are obsolete antiques, and even the Mercruiser drive they put behind the 454 in those years is hard to get parts for.
 

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Discussion Starter #7
The stern leg is supposed to be new. Atleast that's what the guy I brought it off told me. It's too late to turn back now, I've sunk far too much into it that I can't not finish this boat build
 

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if they have the engine apart... DON'T loose any of the used parts.. some of the marine application 454 motors use OVERSIZED OD main bearings. not on the crank side of the bearing that would be the undersize ID.. i am talking about the main bearing bore in the block.. the blocks were HONED OVERSIZE preventing aftermarket bearings from working.

i don't know if there are any of the special main bearings left in the marine parts system.. this is just a shout..

as far as i can tell king bearing made them for GM.. but there are NONE left at king bearing i looked ..
 
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