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Discussion Starter #1
Is 4.253 - 4.254 good for a standard bore on a 454?

I just tore mine down and I'm trying to decide what to do...
 

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It's what we do
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The only way to know what size bore you need is to measure your pistons.
 

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Why does my post have an unhappy face at the top?
 

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Discussion Starter #13
Thanks for the replies. I appreciate all the knowledge here on these boards.

It sounds like you think things would be a tad loose. That's good information to have.

Part of me wants to put this one back together, and part of me wants to order a 540 short block! :)devil

...just weighing all the options.

Thanks again!
 

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Thanks for the replies. I appreciate all the knowledge here on these boards.

It sounds like you think things would be a tad loose. That's good information to have.

Part of me wants to put this one back together, and part of me wants to order a 540 short block! :)devil

...just weighing all the options.

Thanks again!
Hey clutch. without knowing the piston diameter and cast or forged. off the top I would hone and buy .005 over rings and file to fit and be real careful on the beak-in! Your'e numbers are close enough to work and depending on the pocket book and what you want go with it. IMO M
 

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Loose?

4.2445 piston to 4.2545 bore is a bit loose.However, due to cold water cooling the piston grows a bit more than the bore. Remember, boats don't log thousands of miles like a vehicle application......I'd run them until if, and when, it starts sounding like a diesel.....Be careful on ring choice. Material, more so than size. The wrong rings on an old, smooth bore, will have a built in disapointment, and also create a considerable mess on your shiny valvecovers.......MP
 

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Discussion Starter #16
Hmmm, decisions decisions....

Thanks for all the input guys.

BTW - The head on the oil pump pickup came loose and caused the whole problem. Black crank now!
 

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The clearance is already built into all pistons. A 30 over SRP is not 4.28 in dia. Its about .004 smaller. A forged TRW is about .0025 smaller. A cast piston is about .0015 smaller. So if you want .004 clearance with a SRP, boring it to 4.284 would be a huge mistake. You just doubled the built in clearance to .008 at the skirt. BTW your bores are too large to salvage. Bore it to 4.28 and stick in whatever piston you want. Being that this is a cold water appl. go to 4.281 to be safe.
 

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Discussion Starter #18
Yeah, I believe you and many others here are right Machinehead. I've decided to junk the block and build a 540 Dart.

I've also discovered under close examination that #7 has been sleeved and that several deck threads have thread inserts in one bank. It's too bad because it's a desireable block (14015445). Does anyone have any idea what it might be worth in this condition?
 

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Worth?

Yeah, I believe you and many others here are right Machinehead. I've decided to junk the block and build a 540 Dart.

I've also discovered under close examination that #7 has been sleeved and that several deck threads have thread inserts in one bank. It's too bad because it's a desireable block (14015445). Does anyone have any idea what it might be worth in this condition?
Well it used to be a penny a pound for cast iron........J/K....A sleeve and a few helicoils doesn't render a block useless. It will work just fine for a less than all out performance motor. Great for a truck, mild mannered jetboat, or v drive....We use sleeved blocks all the time, and helicoils are the norm these days as all these MK IV blocks are older than dirt............I'd say $200. would be a fair price assuming the buyer is aware of the repairs......MP
 
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