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The Good
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Discussion Starter #1
What is it about a 455 olds that won't rev as high as a ford or chevy? I've heard mostly 5000rpm or less on olds and much higher on the other BB's. what about that engine holds it back from a performance standpoint? just wanted to know.
 

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With good parts and a modifed oiling system they will but the inherent size of the Olds main journal does not lend itself to high rpm power making.
 

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Go with a Chev motor, more performance parts at lower costs. my 2 cents!
 

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The Good
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Discussion Starter #5
I know olds parts are quite a bit more. I plan to have one rebuilt by a shop i feel pretty confident with. I was just curious technically what and why is the olds not a buildable high rev/hp engine. i know cost is some of it but design has to be a factor as well. i'm buliding an engine for a ski boat (19 ' tahiti supertiger) so i'm not looking for a big hp engine. I wanted some insight from someone who could explain it.
 

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Here the long and short. The motor is under square. Which means the bore is smaller than the stroke. Long stroke, small bore. The small bore crowds the valves so they don't flow real well. The heads are a standard wedge design with the valves inline. The Ford and Chevy have larger bores, shorter stroke engines. The Ford and Chevy heads have what is called canted valve heads. The valves lean in a direction that helps flow, and open away from the cylinder walls and combustion chamber walls to encourage flow.

This right here is what made the aftermarket make parts for them. Add in stronger block, stronger rods, stronger crankshafts, etc. and you can see why the aftermarket didn't waste there time and money chasing Buicks, Pontiacs, and Oldsmobiles. No money in it.

There are hundreds of other reasons. But one could write a book on the subject.



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The Good
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Discussion Starter #9
from what i have read the oil issues are primarily too much oil on the valve train and the drainage is poor so the lower end can starve for oil. external oil drain backs directly to a big oil pan should help. I would highly recommend an article called "the Practical Olds" from and old issue of hotboat. google the title and it comes up as a pdf. anybody looking for info on an olds rebuild should read it.
 

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Below about 450-475 HP, stay with Olds and someone who KNOWS OLDS BOAT MOTORS, above that, since you have to change mounts and everything else, a BBFord is the cheapest engine build/ horsepower above 500 HP. I do this for a living, I like to think that I have a clue. The Olds article has a few small discrepancies, and there is more info about them, but it is still a good starting point. You should read it. TIMINATOR
 

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olds 455

I know olds parts are quite a bit more. I plan to have one rebuilt by a shop i feel pretty confident with. I was just curious technically what and why is the olds not a buildable high rev/hp engine. i know cost is some of it but design has to be a factor as well. i'm buliding an engine for a ski boat (19 ' tahiti supertiger) so i'm not looking for a big hp engine. I wanted some insight from someone who could explain it.
You need to keep the oil from pumping up too the top of the motor and stay at the crank ,USE OIL RESTRICTERS . mondello tech book will explain all.
 

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Something else I'd like to add...The Olds heads are more prone to detonation due to their small quench area and spark plug placement. Most of the so called "oiling problems" that were blamed for the countless spun bearings Oldsmobiles were famous for were due to inaudible detonation that pounded the rod bearings similar to tapping a ballpeen hammer on a flat piece of metal. Tap long enough and the metal begins to curl. The bearings curl as well, scraping the oil off the journal. A good indicator of detonation is when you tear an engine down and the rod bearings fall out of the rod, they are starting to curl. Keep an Olds from detonating and it will live.
 
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