Bench Racing 470 CID 400 or 511 CID 383?
#573699
01/05/10 12:02 PM
01/05/10 12:02 PM
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Joined: Sep 2007
Posts: 626
Mid-Ohio
Bakaruda432
OP
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OP
mopar addict
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Mid-Ohio
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A 400 Big Block with a .035 overbore and a 3.91 crank will make 470 CID. A 383 Big Block with a .060 overbore and a 4.375 crank will make 511 CID. Assume Stealth or Edelbrock Victor heads Forged crank, rods, and 7.5:1 Cr pistons and a 6 or 8-71 Supercharger. Which one is the best? Why?  
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: Bakaruda432]
#573700
01/05/10 01:06 PM
01/05/10 01:06 PM
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Joined: Jan 2003
Posts: 10,022
MN
JERICOGTX
I Live Here
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I Live Here
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MN
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I'd take the bigger bore of the 400 any day over the 383. Valve shrouding even on a .060 over 383 is the biggest draw back when trying to make power.
Jeff
69 GTX
68 Road Runner
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: Bakaruda432]
#573706
01/06/10 12:53 AM
01/06/10 12:53 AM
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Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
dodgeboy11
super stock
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super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
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Quote:
A 400 Big Block with a .035 overbore and a 3.91 crank will make 470 CID.
A 383 Big Block with a .060 overbore and a 4.375 crank will make 511 CID.
Assume Stealth or Edelbrock Victor heads Forged crank, rods, and 7.5:1 Cr pistons and a 6 or 8-71 Supercharger.
Which one is the best?
Why?
Supercharged, the valve shrouding is less of an issue, but being boosted, I'd rather run a short stroke and turn some RPM than put the added stress of the longer stroke on that block. If I was going to build a heavily boosted motor, I'd use the 400 block with a 3.75 stroke, or a 3.500 stroke. Less rod angle is easier on the block.
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: Bakaruda432]
#573708
01/06/10 11:06 AM
01/06/10 11:06 AM
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Joined: Jan 2003
Posts: 10,000
Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
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Frostbitefalls MN (Rocky&Bullw...
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For best power out put, the biggest bore shortest stroke for the same cubes always comes up the winner. Simply less friction from rings, for starters. The rings are about 50 percent of the total resistance to rotation in a shortblock.
A larger bore/shorter stroke has much less total drag. Generally more room in the pan area to absorb windage from the piston motion and rotating assembly. Also makes for less total rotating weight and less valve shrouding.
Look at the modern prostock- 4.6+ bores less than 3.7 stroke.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: Bakaruda432]
#573709
01/06/10 11:34 AM
01/06/10 11:34 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
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Grand Haven, MI
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Quote:
A 400 Big Block with a .035 overbore and a 3.91 crank will make 470 CID.
A 383 Big Block with a .060 overbore and a 4.375 crank will make 511 CID.
Assume Stealth or Edelbrock Victor heads Forged crank, rods, and 7.5:1 Cr pistons and a 6 or 8-71 Supercharger.
Which one is the best?
Why?
I'd think you're going to have a hard time with that long of a stroke in a low deck to get pistons with enough dish for that compression, unless you're using super short rods, which would induce major side loading.
if you plan on actually running decent boost to not make the blower a poser piece, I'd probably stick with a 3.75 stroke (451 or 432 depending on block) max and run as long of a rod as possible to minimize side loading and to help the block live. a stock stroke 383 or 400 should be able to make 700+ HP on pump gas with a blower pushing 10-15PSI without turning the revs to the moon, which is pushing the limits of a stock block.
I'd also minimize overbore as much as possible to maximize cyl wall thickness.
assuming pistons at 0 deck....
for a 432 (.030 over 383, 3.75" stroke) with eddie or stealth heads (84cc) and a .040" head gasket, you need a 40cc dish to get 7.5:1. up the stroke to 4.375, you need
a 65cc dish to get 7.5:1...not gonna happen....
for a 451 (.035 over 400, 3.75" stroke) with eddie or stealth heads (84cc) and a .040" head gasket, you need a 48cc dish to get 7.5:1. up the stroke to 3.9, you need
a 53cc dish to get 7.5:1...not gonna happen very easily
stock stroke, you'd need a 28 and 33 cc dish, respectively...
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: gregsdart]
#573710
01/06/10 12:16 PM
01/06/10 12:16 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
For best power out put, the biggest bore shortest stroke for the same cubes always comes up the winner. Simply less friction from rings, for starters. The rings are about 50 percent of the total resistance to rotation in a shortblock.
A larger bore/shorter stroke has much less total drag. Generally more room in the pan area to absorb windage from the piston motion and rotating assembly. Also makes for less total rotating weight and less valve shrouding.
Look at the modern prostock- 4.6+ bores less than 3.7 stroke.
sounds like a 340 
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: Quicktree]
#573711
01/12/10 11:24 AM
01/12/10 11:24 AM
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Joined: Sep 2007
Posts: 626
Mid-Ohio
Bakaruda432
OP
mopar addict
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OP
mopar addict
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Posts: 626
Mid-Ohio
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It sounds like the best combo for a blown engine is +.035 overbore 400 w/3.75 crank (451 cid) or +.030 383w/ same crank (432 cid). It seems like E-85 fuel+ Water injection or 91-93 octane pump gas w Methanol& Water injection is allowing for higher Static compression ratio such as 8-9.2:1. It also seems like the 6-8-71 Blower is a great Old School touch but the Procharger wins in terms of efficiency. How right on am I? Do I get a or a  ? I want your
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Re: Bench Racing 470 CID 400 or 511 CID 383?
[Re: Quicktree]
#573712
01/12/10 02:58 PM
01/12/10 02:58 PM
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Joined: Nov 2004
Posts: 2,825
Sk. Canada
RemCharger
master
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master
Joined: Nov 2004
Posts: 2,825
Sk. Canada
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Quote:
Quote:
For best power out put, the biggest bore shortest stroke for the same cubes always comes up the winner. Simply less friction from rings, for starters. The rings are about 50 percent of the total resistance to rotation in a shortblock.
A larger bore/shorter stroke has much less total drag. Generally more room in the pan area to absorb windage from the piston motion and rotating assembly. Also makes for less total rotating weight and less valve shrouding.
Look at the modern prostock- 4.6+ bores less than 3.7 stroke.
sounds like a 340
383. The "Schwarzennegger" version of the 340. 
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I'll bet mine is 517, not 518 
4.375 bore by 4.300 stroke 
400 bored + 040 
