block bore question

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block bore question

Post  cobrakid8 on November 30th 2017, 9:38 am

Alright guys, so I have been doing a search and it seems like with a stock block the biggest stroke without clearancing is 4.5. My question is what is the safest bore with a filled block you can do? Guy I am talking to has one that is 4.5 stroke and he says 4.5 bore with a stock 70 model block for he said a total of 565(CID chart shows) 572 on here. So is 4.5 bore safe with a filled block or is that just to much to go for a stock block? If i built one myself it would prob be the 557 that i keep hearing is the most you can go safely before going to aftermarket.

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Re: block bore question

Post  rmcomprandy on November 30th 2017, 9:55 am

cobrakid8 wrote:Alright guys, so I have been doing a search and it seems like with a stock block the biggest stroke without clearancing is 4.5. My question is what is the safest bore with a filled block you can do? Guy I am talking to has one that is 4.5 stroke and he says 4.5 bore with a stock 70 model block for he said a total of 565(CID chart shows) 572 on here. So is 4.5 bore safe with a filled block or is that just to much to go for a stock block? If i built one myself it would prob be the 557 that i keep hearing is the most you can go safely before going to aftermarket.

SOME ...

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Re: block bore question

Post  IDT-572 on November 30th 2017, 12:54 pm

X2,

But I wouldn't think it would be worth the effort. between a 557 and a 572, a bad tune would bridge the HP gap between the two.

But if I was going to a class where every HP counted, I would sonic check the bores and fill to the deck and try to run alky.

A friend of mine ran one this way on gas in a pulling truck at 16:1 compression and didn't have any problems for two years.
(PROBABLY LUCKY)

Just fill it and let it cure good before you bore it.
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Re: block bore question

Post  Paul Kane on November 30th 2017, 1:52 pm

cobrakid8 wrote:...what is the safest bore with a filled block you can do? Guy I am talking to has one that is 4.5 stroke and he says 4.5 bore with a stock 70 model block...is 4.5 bore safe with a filled block or is that just to much to go for a stock block?
It depends on the actual cylinder block and the application of the engine.  Typically, for big bore stock block builds the block needs to be hand-picked based on a sonic check evaluation of its overbore capability.  Blocks that can be safely bored to 4.500" are not common but they are certainly out there...more so if you are filling the water jackets solid.

cobrakid8 wrote:...i keep hearing (0.080") is the most you can go safely before going to aftermarket.
Most people who are telling you "beyond 0.080 you have to go aftermarket block" probably never even built a big bore stock block engine and probably never will--they are just internet rhetoric guys.

I have a DIVE block over here that I would trust to 1000 hp at 4.500" bore, unfilled.


Last edited by Paul Kane on November 30th 2017, 10:32 pm; edited 1 time in total
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Re: block bore question

Post  Paul Kane on November 30th 2017, 1:54 pm

IDT-572 wrote:A friend of mine ran one this way on gas in a pulling truck at 16:1 compression and didn't have any problems for two years.
(PROBABLY LUCKY)

Probably smart (ie, understands well what he is doing and how to do it).
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Re: block bore question

Post  Frank Merkl on December 2nd 2017, 2:53 am

My DOVE A block made over 1400 hp on 2 kits and it still sits on the shelf as a good backup motor , as I cannot bear to sell it as it's beaten every stock block chevy or mopar on the dyno for HP on the dyno !!! and there is a board in the dyno cell with what most of them have made but we set the bar High!!
Frank
it sits waiting to defend it's title !
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Re: block bore question

Post  BBFTorino on December 2nd 2017, 4:40 am

Frank Merkl wrote:My DOVE A block made over 1400 hp on 2 kits and it still sits on the shelf as a good backup motor , as I cannot bear to sell it as it's beaten every stock block chevy or mopar on the dyno for HP on the dyno !!! and there is a board in the dyno cell with what most of them have made but we set the bar High!!
Frank
it sits waiting to defend it's title !
That's part of the family right there!! Wink

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Re: block bore question

Post  cobrakid8 on December 2nd 2017, 9:00 am

Thanks guys, the guy that has the motor stated that when it was put together everything was sonic tested and it had plenty of meat still left. I just had never heard one going that big and was kind of afraid of it, thinking he was full of crap. Guess we will see when I hopefully go and pick it up, it will be naturally aspirated and ran on alky.

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Re: block bore question

Post  stanger68 on December 3rd 2017, 12:03 am

Frank Merkl wrote:My DOVE A block made over 1400 hp on 2 kits and it still sits on the shelf as a good backup motor , as I cannot bear to sell it as it's beaten every stock block chevy or mopar on the dyno for HP on the dyno !!! and there is a board in the dyno cell with what most of them have made but we set the bar High!!
Frank
it sits waiting to defend it's title !

Frank, was that 2 bolt block? Was anything done to alter the mains?

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Re: block bore question

Post  Mark Miller on December 3rd 2017, 1:36 am

Frank Merkl wrote:My DOVE A block made over 1400 hp on 2 kits and it still sits on the shelf as a good backup motor , as I cannot bear to sell it as it's beaten every stock block chevy or mopar on the dyno for HP on the dyno !!! and there is a board in the dyno cell with what most of them have made but we set the bar High!!
Frank
it sits waiting to defend it's title !

Frank,that's awesome take that Bowtie and Mopar boys!!!! Smile Smile

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Re: block bore question

Post  jbozzelle on December 3rd 2017, 12:33 pm

What's your intended purpose?  If it's just a street/strip deal then just do a 545.  Keep that bore small for some future rebuilds...

Don't get hung up on the "have to have all the cubes I can get" bandwagon...  Unless you're running a specific class.  In which I would assume aftermarket blocks would be allowed and you wouldn't be asking your question...

My little 514 is going to suit me just fine and run in the low 9s. More than enough for what it has. You'll get more out of a set of heads that a little more bore...

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Re: block bore question

Post  cobrakid8 on December 3rd 2017, 12:47 pm

jbozzelle wrote:What's your intended purpose?  If it's just a street/strip deal then just do a 545.  Keep that bore small for some future rebuilds...

Don't get hung up on the "have to have all the cubes I can get" bandwagon...  Unless you're running a specific class.  In which I would assume aftermarket blocks would be allowed and you wouldn't be asking your question...

My little 514 is going to suit me just fine and run in the low 9s.  More than enough for what it has.  You'll get more out of a set of heads that a little more bore...

It's for a strip deal on a pipe rack, my budget for a build will be whatever I get out of the BBC I am trying to sell and this is a guy that wants to trade for my motor so it's already put together and it's never been run. I figured run it a year and hopefully at that point move to an aftermarket block, I pretty much have no racing budget so it's whatever I can scrape together after paying bills and what not is what I can do and my son is moving from a junior to a big dragster. I don't think there is any way I can build a motor with the money that I will have fromselling the Chevy compared to what he has in this motor. My idea was to build a cheap 557 or about that size but there's no money in Chevy motors it seems and this guy has a new Malibu he wants to put my motor into.

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Re: block bore question

Post  Paul Kane on December 3rd 2017, 4:02 pm

stanger68 wrote:
Frank Merkl wrote:My DOVE A block made over 1400 hp on 2 kits ...

Frank, was that 2 bolt block? Was anything done to alter the mains?
Not Frank, but this much I know about his engine:

  • D0VE-A block with splayed 4-bolt caps on 2, 3, & 4
  • 4.50" Bore
  • Short fill (ie, bottom of water pump holes)
  • 1428 hp @ 7500 rpm
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Re: block bore question

Post  Frank Merkl on December 3rd 2017, 4:51 pm

and the hp was still going up at 7500
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Re: block bore question

Post  BBFTorino on December 3rd 2017, 6:51 pm

Can you elaborate on the rest of the combo, Frank??

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Re: block bore question

Post  jbozzelle on December 3rd 2017, 8:52 pm

cobrakid8 wrote:

It's for a strip deal on a pipe rack, my budget for a build will be whatever I get out of the BBC I am trying to sell and this is a guy that wants to trade for my motor so it's already put together and it's never been run. I figured run it a year and hopefully at that point move to an aftermarket block, I pretty much have no racing budget so it's whatever I can scrape together after paying bills and what not is what I can do and my son is moving from a junior to a big dragster. I don't think there is any way I can build a motor with the money that I will have fromselling the Chevy compared to what he has in this motor. My idea was to build a cheap 557 or about that size but there's no money in Chevy motors it seems and this guy has a new Malibu he wants to put my motor into.


Hit up Qtrwarrior on here. Mike's got a few piperack combos he can share with you. My 514, with about 750 hp in his old 236" Undercover went 5.50 peddling the low to high shift...

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Re: block bore question

Post  QtrWarrior on December 4th 2017, 5:36 am

jbozzelle wrote:
cobrakid8 wrote:

It's for a strip deal on a pipe rack, my budget for a build will be whatever I get out of the BBC I am trying to sell and this is a guy that wants to trade for my motor so it's already put together and it's never been run. I figured run it a year and hopefully at that point move to an aftermarket block, I pretty much have no racing budget so it's whatever I can scrape together after paying bills and what not is what I can do and my son is moving from a junior to a big dragster. I don't think there is any way I can build a motor with the money that I will have fromselling the Chevy compared to what he has in this motor. My idea was to build a cheap 557 or about that size but there's no money in Chevy motors it seems and this guy has a new Malibu he wants to put my motor into.


Hit up Qtrwarrior on here.  Mike's got a few piperack combos he can share with you.  My 514, with about 750 hp in his old 236" Undercover went 5.50 peddling the low to high shift...

Yup, I sure do... Would be glad to help !! You would be surprised how cheap you can build a "starter" motor for...Especially for a Jr going to a big car...Just shoot me a PM...
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