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Discussion Starter #1
What is the largest cubic inch BBC you can make from a short deck aftermarket block?

Looking at a pump gas engine but am worried about tall deck headers for an A-body. Lemons seem to be the way to go but I'm not interested in cutting up our inner fenders. Seems to me short deck headers would be easier to find or have made?
 

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Confused Racer
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598 is about it with a 4.840BS and a 9.8 deck. 582 is a little more comfortable. and lemons is the only header to use
 

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I'd stop at 582 and be happy. Cutting the wheelwells is no big deal. You can always buy a set of aftermaket inner's to cut and save your originals. I bought used inner's and saved the originals. Lemons wrap around headers fit like a glove.
 

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whilst largely I would very much agree with the above,,,,, depending on the application,,, I possibly would stop at the 4.250'' crank rather than the 4.375'' deal,,, and especially so given your admission of wanting to run on pump swill.
 

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T/S 368E
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I've had several 557-582's and I'm probably going back to a 1/4" arm next time I break the crank.

I'm no expert, but I don't like stuffing a 1/2" in a 9.8.
I don't like the piston now, no way I would use the 1/2".
That being said, plenty of guys are running great like that, so who knows.

.
 

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Aviation Section
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Blueprint 598 short block is a 9.8 deck, 4.495 bore, $5499 with a warranty and free shipping if you buy from Jegs or Summit. All the parts are new, not rebuilt. Don't think you could build one for what this new one costs and they offer a free dyno test!, how they do that on a shortblock is the question, maybe they just spin it.

https://blueprintengines.com/produc...e-engine-big-block-gm-style-shortblock-ps5980

Dave
 

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Blueprint 598 short block is a 9.8 deck, 4.495 bore, $5499 with a warranty and free shipping if you buy from Jegs or Summit. All the parts are new, not rebuilt. Don't think you could build one for what this new one costs and they offer a free dyno test!, how they do that on a shortblock is the question, maybe they just spin it.

https://blueprintengines.com/produc...e-engine-big-block-gm-style-shortblock-ps5980

Dave

A friend of mine machined one of their blocks. He said it's about as soft as a production block, nothing like Dart/World/Bowtie
 

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I would not let headers dictate the engine that I would build. The parts cost all about the same for anything aftermarket. Costs about the same to build a 540 as it does to go 598,615. Anything larger should go to a spread port head.
Have the proper headers built from scratch instead of buying something that may or may not fit or work optimal.
 

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T/S 368E
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No frigging way I'm putting an arm that big in a 9.8, I don't give a damn what any one says.
Obviously he is a real expert and I'm a nobody that is writing the checks!!!

It is not worth the little bit of power 30 inches gives you.

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No frigging way I'm putting an arm that big in a 9.8, I don't give a damn what any one says.
Obviously he is a real expert and I'm a nobody that is writing the checks!!!

It is not worth the little bit of power 30 inches gives you.

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Agree 100%. There's a point of diminishing returns and I think anything over 4.25" is heading that direction. Windage has to be a bitch and the rod angle is pretty damned severe.
 

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T/S 368E
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I hate the rod, ring & piston compromises you make to fit all that in there.
I will absolutely be switching to a 1/4" arm next time I buy a crank.
Unless of course it's a catastrophic failure and then I will get a much taller deck!!!

.
 

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Lot's of opinions on this so what the hell, I'll throw mine in there, 9.8 deck I'd go 582 max, 10.2 deck 615 max, of course YMMV.
 

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T/S 368E
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GEESH, for years the 632" N2O engine was the most common one out there.
I don't like that combination, but I would never say "it's no good".
Plenty of them out there in a dozen classes!!!! Running fine & strong!!!

.
 

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10.2 632 w/raised cam tunnel is nice. Especially if you want to run aluminum rods.
 
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