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Re: compare 496 b & 499 rb [Re: Performance Only] #1135016
12/17/11 07:31 PM
12/17/11 07:31 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
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Weddington, N.C.
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.


WIZE

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Re: compare 496 b & 499 rb [Re: Streetwize] #1135017
12/17/11 11:07 PM
12/17/11 11:07 PM
Joined: Jan 2010
Posts: 1,074
st.cloud fl
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d-150 Offline
Smarter than a 5th grader?
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st.cloud fl
best advantage is the b block gives a little more room under the hood. i think 440 get a bad rap for cracking. if you have 2 million 440 blocks compared to 3 hundred thousand 400 blocks your probably going to see more cracked 440s

Re: compare 496 b & 499 rb [Re: 68roadrunner] #1135018
12/18/11 12:19 AM
12/18/11 12:19 AM
Joined: Jun 2009
Posts: 877
ky
68roadrunner Offline OP
super stock
68roadrunner  Offline OP
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ky
fftopic


this post was supposed to be about the performance difference between a 4.31x4.25 stroke compared to a4.375x4.150 stroke.

Re: compare 496 b & 499 rb [Re: 68roadrunner] #1135019
12/18/11 06:03 AM
12/18/11 06:03 AM
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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Performance Only Offline
top fuel
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Delray beach, Florida
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
Re: compare 496 b & 499 rb [Re: 68roadrunner] #1135020
12/18/11 08:30 AM
12/18/11 08:30 AM
Joined: Jan 2003
Posts: 9,963
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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Frostbitefalls MN (Rocky&Bullw...
Quote:


The lower rod ratio will increase the bottom end and the added stroke will offset the smaller bore difference.

that is what i was getting at. so you are saying the extra stroke 4.250 over 4.150 will help overcome the bore difference of .065 .

would a different cam and head port size help the smaller bore fill better. would you use a smaller faster port or not


The ports you use will determine total output in torque and hp. The bigger bore will help airflow some. The rod ratio differences may or may not make a difference, and a lot better minds than mine disagree on that subject. Read the tech pages on the Reher Morrison web site. From my perspective the reasons to go with one over the other is based on bore size, and ultimately on how hard I am going to push to blocks. The 383 Vs the 440 is kind of an unknown when you look at their bottom end strength, and the difference may not be that much based on the info on the 440 source page on blocks. Neither is a good candidate for power over somewhere north of 650 hp.


8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: compare 496 b & 499 rb [Re: gregsdart] #1135021
12/18/11 11:29 AM
12/18/11 11:29 AM
Joined: Mar 2007
Posts: 621
Iowa
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coronetville Offline
mopar
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Iowa
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

Re: compare 496 b & 499 rb [Re: Performance Only] #1135022
12/18/11 12:15 PM
12/18/11 12:15 PM
Joined: Jun 2009
Posts: 877
ky
68roadrunner Offline OP
super stock
68roadrunner  Offline OP
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Posts: 877
ky
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

Re: compare 496 b & 499 rb [Re: coronetville] #1135023
12/18/11 12:15 PM
12/18/11 12:15 PM
Joined: Jan 2003
Posts: 9,963
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
master
gregsdart  Offline
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Posts: 9,963
Frostbitefalls MN (Rocky&Bullw...
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..603 156 mph best, 2905 lbs 549, indy 572-13, alky
Re: compare 496 b & 499 rb [Re: gregsdart] #1135024
12/18/11 02:15 PM
12/18/11 02:15 PM
Joined: Apr 2011
Posts: 319
jonestown,pa
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dmking Offline
enthusiast
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jonestown,pa
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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