Re: compare 496 b & 499 rb
[Re: Performance Only]
#1135016
12/17/11 07:31 PM
12/17/11 07:31 PM
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Joined: Jan 2003
Posts: 9,924 Weddington, N.C.
Streetwize
master
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master
Joined: Jan 2003
Posts: 9,924
Weddington, N.C.
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The low deck is roughly 7% shorter so as Dan said it's not really as significant as some think. However the rotating mass is that much ccloser to the crank and the low deck will have a lower center of gravity all else being equal. any block is only as strong as it's thinnest bore. Thew main advantage to the low deck ( to me) is they used to be cheap to find and the smaller journals on both the rods and mains (when you go 2.200) just helps the bottom end spin a little easier. and generally lighter is (if little more) extra insurance for when you over-rev. Headflow, cam and compression pretty much determine the sweet spot and the rev cieling, lighter bottom ends just get there a little easier and are 'less brutal' to themselves at thigh rpm. Expert machining is the key to a great running motor, Typically experienced builders can tell how well a motor will run by the way it falls together, and also how well (or poorly) it ran by how it comes apart.
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Re: compare 496 b & 499 rb
[Re: 68roadrunner]
#1135019
12/18/11 06:03 AM
12/18/11 06:03 AM
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Joined: Jul 2010
Posts: 2,091 Delray beach, Florida
Performance Only
top fuel
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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Quote:
this being a race only piece. using same cam, heads, compression, everything. how would a 496 4.31x4.25 compare to a 499 4.375x4.15. i am sure the smaller bore would hurt flow some, but would have a lighter rotating weight. so what does everyone think?
the way the question is worded makes it pretty generic. your not offering any specifics for the build regarding the heads, cam, compression, intake manifold, etc. etc. or for the car it would go in. if this is a build your actually considering, the answers would be better if you added some information.
machine shop owner and engine builder
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Re: compare 496 b & 499 rb
[Re: Performance Only]
#1135022
12/18/11 12:15 PM
12/18/11 12:15 PM
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Joined: Jun 2009
Posts: 877 ky
68roadrunner
OP
super stock
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OP
super stock
Joined: Jun 2009
Posts: 877
ky
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Quote:
Quote:
this being a race only piece. using same cam, heads, compression, everything. how would a 496 4.31x4.25 compare to a 499 4.375x4.15. i am sure the smaller bore would hurt flow some, but would have a lighter rotating weight. so what does everyone think?
the way the question is worded makes it pretty generic. your not offering any specifics for the build regarding the heads, cam, compression, intake manifold, etc. etc. or for the car it would go in. if this is a build your actually considering, the answers would be better if you added some information.
okay, 13-1 compression flattop zero deck,284 288 680 lift lsa 108, -1 heads 2.19&1.81 325cc cnc port flow 355 or so, dominater on alky
i know how this runs in a 440 block with a 4.150&4.375 how would this run in a 383 with 4.31x4.25 stroke
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Re: compare 496 b & 499 rb
[Re: coronetville]
#1135023
12/18/11 12:15 PM
12/18/11 12:15 PM
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Joined: Jan 2003
Posts: 10,088 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,088
Frostbitefalls MN (Rocky&Bullw...
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Quote:
I think the this topic started with using a .60 over 383 block and a 440 block, that he had. the 400 block wasnt the in the question
Thats why my last post says what it says. All posts so far have tried to provide help, and a lot of us believe the right direction is to bail on the 383 and 440 block and go 400. But that is up to the OP and what he intends to do with the combo. If it is a low power bracket combo, and a few hp lost to the small bore is of no concern, he may chose to go that way (383) and it would be fine. Ditto on the 440 block if the cylinder walls check out better and it makes a better low hp bracket motor, the choice may be the 440.
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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Re: compare 496 b & 499 rb
[Re: gregsdart]
#1135024
12/18/11 02:15 PM
12/18/11 02:15 PM
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Joined: Apr 2011
Posts: 320 jonestown,pa
dmking
enthusiast
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enthusiast
Joined: Apr 2011
Posts: 320
jonestown,pa
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well i would go with the 440 block over the 383 and stay under 680hp. the 383 looks weaker than the 440 botom end with the middle mains even smaller than the small older 440s. i just took apart a nother 6630-440 block with .520 middle mains. those are real close to the good 400block thickness by .030 but not the hard to fine super block 440source talks about 400 wise anyway. someone around my area says "my engine builder says" the 383 block is a stronger setup over a 440. well one would not know that just looking at it and mesuring things. and i am now gun shy since i split my 73 440 block.
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