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Re: 632 crate engine
[Re: AndyF]
#3104908
12/23/22 02:24 PM
12/23/22 02:24 PM
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Joined: May 2004
Posts: 12,478
Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
Posts: 12,478
Taxes & Virus's R-US, NY
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One of the best deals on the planet for the money.....
Can't wait to face a whole field full of them this summer with my stock block 440Source stroker...
Last edited by Dragula; 12/23/22 02:24 PM.
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Re: 632 crate engine
[Re: fast68plymouth]
#3104911
12/23/22 02:42 PM
12/23/22 02:42 PM
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Joined: Jan 2003
Posts: 31,228
Oregon
AndyF
OP
I Win
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OP
I Win
Joined: Jan 2003
Posts: 31,228
Oregon
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The guy has a Hogan intake that he wants to try. Evidently Hogan is already making parts for this engine. The intake looks conventional but it really isn't since the heads are unique and the coils are mounted under the runners. We haven't taken a close look at the engine yet but the heads are obviously a different design than regular big blocks. First glance is that they are similar to a Ford 429/460 but I'm sure the GM engineers would disagree. They would probably say it is a GM Pro Stock design. I'll post pictures when I get them. I haven't' seen under the valve covers yet.
Last edited by AndyF; 12/23/22 02:52 PM.
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Re: 632 crate engine
[Re: AndyF]
#3104944
12/23/22 04:16 PM
12/23/22 04:16 PM
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Joined: Jan 2003
Posts: 7,533
Minnesota
Hemi_Joel
master
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master
Joined: Jan 2003
Posts: 7,533
Minnesota
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What is the bore and stroke on that thing?
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: 632 crate engine
[Re: AndyF]
#3104958
12/23/22 05:07 PM
12/23/22 05:07 PM
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Joined: Jan 2003
Posts: 7,533
Minnesota
Hemi_Joel
master
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master
Joined: Jan 2003
Posts: 7,533
Minnesota
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Intake flow: 481 cfm @ 0.787"
Exhaust flow: 347 cfm @ 0.787"
A good set of Hemi heads would have no problem trumping those numbers. What advantage this Chevy has is the big bore.
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: 632 crate engine
[Re: Dragula]
#3104981
12/23/22 06:27 PM
12/23/22 06:27 PM
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Joined: Aug 2005
Posts: 775
Southington Ct.
turbobitt
super stock
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super stock
Joined: Aug 2005
Posts: 775
Southington Ct.
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Those are some really nice looking heads. The exhaust and intake ports are raised up a bunch and a nice small chamber. I bet the valves are rotated a bunch from factory. .
AG.
1970 Challenger w/572 Hemi street car and my pride and joy.
1986 T-Type with 272 Stage 2 Buick V6 engine - True 8 second street car. Just updated the engine and put down 928 HP @ 35# boost to the ground on chasis dyno.
1976 Cee Bee Avenger Jet Boat - 460 Ford powered.
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Re: 632 crate engine
[Re: AndyF]
#3105004
12/23/22 07:13 PM
12/23/22 07:13 PM
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Joined: Oct 2007
Posts: 4,219
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,219
New York
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Head CFM is nice, but the head does many other things.
Some smart person said (paraphrased) the absolute limit to intake port efficiency is "how tall is the head casting?"
The hemi chamber was a production item as far back as the 1920s (and racing before that), when the belief was that (nearly) pure geometric shapes were inherently efficient: 50% hemisphere with diameter equal to bore diameter, identical intake and exhaust cams, and symmetrically opposed intake and exhaust valves @ 45° angles. Obviously the 392 is closer to this than the 426, despite being only 13 (?) years older.
The hemi chamber shape has limited toroidal swirl*, minimal quench*, the charge isn't directed to a useful target (spark plug and/or exhaust valve), and no influence on cross-flow during overlap.
* As the bore increases beyond chamber diameter some of these factors decay - but the surface-to-volume ratio (the original concept for the hemi: WW1) slowly disappears.
We now know that much shallower valve angles work very well (as long as the port is tall), a much smaller chamber (= smaller dome) can greatly improve overlap flow (without increasing the OL duration in degrees), and that assignment to value must prioritize the intake valve (and limit the exhaust valve as necessary: HT Jon Kaase).
Boffin Emeritus
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Re: 632 crate engine
[Re: polyspheric]
#3105076
12/23/22 10:48 PM
12/23/22 10:48 PM
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Joined: Aug 2005
Posts: 775
Southington Ct.
turbobitt
super stock
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super stock
Joined: Aug 2005
Posts: 775
Southington Ct.
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Head CFM is nice, but the head does many other things.
Some smart person said (paraphrased) the absolute limit to intake port efficiency is "how tall is the head casting?"
The hemi chamber was a production item as far back as the 1920s (and racing before that), when the belief was that (nearly) pure geometric shapes were inherently efficient: 50% hemisphere with diameter equal to bore diameter, identical intake and exhaust cams, and symmetrically opposed intake and exhaust valves @ 45° angles. Obviously the 392 is closer to this than the 426, despite being only 13 (?) years older.
The hemi chamber shape has limited toroidal swirl*, minimal quench*, the charge isn't directed to a useful target (spark plug and/or exhaust valve), and no influence on cross-flow during overlap.
* As the bore increases beyond chamber diameter some of these factors decay - but the surface-to-volume ratio (the original concept for the hemi: WW1) slowly disappears.
We now know that much shallower valve angles work very well (as long as the port is tall), a much smaller chamber (= smaller dome) can greatly improve overlap flow (without increasing the OL duration in degrees), and that assignment to value must prioritize the intake valve (and limit the exhaust valve as necessary: HT Jon Kaase). Kaase knows his stuff. I got a set of his SR-71 460 heads for my boat motor and they have very shallow valve angle, very small combustion chamber, raised intake port, raised roof on the intake and exhaust. Intake flow unported exceeds 400 CFM @ .600 lift and beyond. Price on those is super affordable... AG  
1970 Challenger w/572 Hemi street car and my pride and joy.
1986 T-Type with 272 Stage 2 Buick V6 engine - True 8 second street car. Just updated the engine and put down 928 HP @ 35# boost to the ground on chasis dyno.
1976 Cee Bee Avenger Jet Boat - 460 Ford powered.
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Re: 632 crate engine
[Re: AndyF]
#3105112
12/24/22 06:47 AM
12/24/22 06:47 AM
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Joined: Mar 2003
Posts: 9,116
Rogue River, OR
Jeremiah
master
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master
Joined: Mar 2003
Posts: 9,116
Rogue River, OR
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The 385 platform is hard to beat with it's inherent design benefits and relatively compact design. Add shaft rockers and you are good to go (I hate dealing with stud girdles etc).
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Re: 632 crate engine
[Re: Hemi_Joel]
#3105985
12/27/22 08:10 PM
12/27/22 08:10 PM
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Joined: Jun 2006
Posts: 5,177
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,177
CT
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Intake flow: 481 cfm @ 0.787"
Exhaust flow: 347 cfm @ 0.787"
A good set of Hemi heads would have no problem trumping those numbers. What advantage this Chevy has is the big bore. Wrong forum to point that out in
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: 632 crate engine
[Re: GTX MATT]
#3106040
12/27/22 11:23 PM
12/27/22 11:23 PM
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Joined: Aug 2003
Posts: 43,794
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,794
Bend,OR USA
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Intake flow: 481 cfm @ 0.787"
Exhaust flow: 347 cfm @ 0.787"
A good set of Hemi heads would have no problem trumping those numbers. What advantage this Chevy has is the big bore. Wrong forum to point that out in For the Cheby motor?    I'm thinking that a good set of Predator heads will match or, hopefully, exceed those numbers 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 632 crate engine
[Re: Cab_Burge]
#3106046
12/28/22 12:04 AM
12/28/22 12:04 AM
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Joined: Jan 2003
Posts: 7,533
Minnesota
Hemi_Joel
master
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master
Joined: Jan 2003
Posts: 7,533
Minnesota
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OK, I got curious and looked up the Stave V replacement heads that FHO did for me, just to compare with the chevy. Intakes were about the same, the chevy did more on the intake,
Exhaust Port with 1.90" Valve Intake Port with 2.30" Valve
Flowed at 28" without tube. Flowed at 28"
.100" 59 .100" 76
.200" 130 .200" 164
.300" 184 .300" 245
.400" 232 .400" 320
.500" 265 .500" 396
.550" .550"
.600" 285 .600" 451
.650" .650"
.700" 297 .700" 479
.750" .750"
.800" 308 .800" 488
.900" 314 .900" 488
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: 632 crate engine
[Re: Cab_Burge]
#3106125
12/28/22 02:30 PM
12/28/22 02:30 PM
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Joined: Jan 2003
Posts: 19,563
Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,563
Las Vegas
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I'm thinking that a good set of Predator heads will match or, hopefully, exceed those numbers They do but making power is not just about cylinder head CFM. And there are BBC heads(heads that bolt to stock architecture) that flat out make a Predators head flow seem paltry. While a Predator can move some air it has its issues as well and not having a larger bore size is just one of those. It will be interesting when we dyno my Predator and 600-13 engines on the same day here hopefully next month. Certainly wildly different style heads for certain. I am willing to bet power will be similar between the two. The -13 engine is a much larger, but it is essentially and overgrown -1 head or as I like to say SBC on steroids  But still will be interesting.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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