423 SBC combo help

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Fatman
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Re: 423 SBC combo help

Post by Fatman »

maxracesoftware wrote: Sat Aug 22, 2020 6:21 pm
AFR 227CC CNC'd out-of-box-shape Port Specs :
Intake Port CenterLine Length = 5.488
Exhaust Port CenterLine Length= 2.888

Flow Tests from 3 different pairs of AFR 227CC

1 Pair Ported to 231.0 CC Intake Ports
Flow tested on 4.000 Bore Fixture
Angle-milled + straight cut

other 2 Pairs, Flow tested on 4.125 Bore Fixture
out-the-box shape
Did the heads tested on the 4" bore have a 4" chamber or bigger? How do you think they would have gone on a 4.125-4.155 fixture?
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Re: 423 SBC combo help

Post by maxracesoftware »

Fatman :
Did the heads tested on the 4" bore have a 4" chamber or bigger? How do you think they would have gone on a 4.125-4.155 fixture?
i used a 4.000 Bore Flow fixture because he used a 4.000" Bore Block for this Engine , i can't remember his reason why ??, this is very rare to do this !
but from experience ... it would have gained pretty much Flow CFM in Low to Mid-Lift Valve Lift Range...and a little at higher Lifts

it would have easily been in the 325+ CFM range
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Re: 423 SBC combo help

Post by enigma57 »

Larry, off topic but y'all take care there with these 2 back to back hurricanes headed your way......

https://weather.com/storms/hurricane/ne ... =hp-slot-1

Best regards,

Harry
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Re: 423 SBC combo help

Post by maxracesoftware »

enigma57 wrote: Sun Aug 23, 2020 2:51 am Larry, off topic but y'all take care there with these 2 back to back hurricanes headed your way......

https://weather.com/storms/hurricane/ne ... =hp-slot-1

Best regards,

Harry
Harry ... many thanks for the concern !
yes 2 back-to-back "potential" Hurricanes ... 1 on Monday , 2nd one on Wednesday :)

Harry ,
i go to this site to checkout/track Hurricanes ( no advertisements on page :) )
https://www.nhc.noaa.gov/

and another good Link to see Wind patterns :
https://www.windy.com/30.021/-92.183?29.477,-92.183,8

and if you like Weather Models , i don't think you can find 1 place that has it all, better than this Link :
https://spaghettimodels.com/
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Re: 423 SBC combo help

Post by Fatman »

maxracesoftware wrote: Sun Aug 23, 2020 2:37 am
Fatman :
Did the heads tested on the 4" bore have a 4" chamber or bigger? How do you think they would have gone on a 4.125-4.155 fixture?
i used a 4.000 Bore Flow fixture because he used a 4.000" Bore Block for this Engine , i can't remember his reason why ??, this is very rare to do this !
but from experience ... it would have gained pretty much Flow CFM in Low to Mid-Lift Valve Lift Range...and a little at higher Lifts

it would have easily been in the 325+ CFM range
Does the .93I/.90E in the notes on the ported head mean 93% intake throat? If it does, why so big?
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Re: 423 SBC combo help

Post by enigma57 »

Thanks, Larry! Excellent links! Earlier projections had 1st storm coming our way. Now its expected to come ashore near y'all and then turn our way.

Too early to tell how accurate these projections are but wherever these 2 storms end up going, it won't be much fun there for a while. Stay safe now.

Best regards,

Harry
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Re: 423 SBC combo help

Post by maxracesoftware »

Fatman :
Does the .93I/.90E in the notes on the ported head mean 93% intake throat? If it does, why so big?
this engine was sold , detuned in this Thread ....
makes more HP with these Throats at .93I/.90E at higher RPMs on the "original" Combo at this Link :

viewtopic.php?p=873681#p873681

Chevy Beretta 2450 Lbs runs 8.39 ET 162+ MPH ( all Motor HP , no NOS runs )
with Dart Pro 1 215cc Ported to 245Cc Int Ports
4.187x4.000=440.6cid
Peak TQ = 589.3 @ 6600
Peak HP = 807.5 @ 8300
600 rpm/sec
-----------------------------------
on old TV show "Passtime"
it ran
60 FT= 1.089
330 Ft= 3.110
660 Ft= 4.797 - 145.83 MPH
1000 Ft= 6.251
1320 Ft= 7.493 at 186.36 MPH

4.30 gear
2450 lb
325 HP Nos Nitrous Kit :)
-------------------------------------
later made 816 Peak HP @ 8200 RPM
ran 8.28 ET in killer Air, all Motor

on a refresh , did a little more Port work
then it made 815.8 Peak HP @ 8200 RPM
ran its fastest Pass like that
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Re: 423 SBC combo help

Post by allens »

maxracesoftware wrote: Sun Aug 23, 2020 12:37 am
i ran your Engine Data thru 3 Simulation programs and you should be able to make
about 614 Peak HP to 620+ Peak HP anywhere at 6600 RPM to 6800 RPM max with your current combo
sorted out .... meaning after problem areas are fixed !
i forgot to mention :
in all 3 Engine simulations i used :
285.0 Intake Flow CFM
207.0 Exhaust Flow CFM
... those were approx CFM numbers for "out-the-box" AFR 227CNC'd
at your current Cam's Valve Lifts
Thanks Larry, that's a lot of information!

We can hopefully get it optimized as-is, sounds like we may have another weekend at the track this year, and then possibly try some dyno time this winter.

If we're wanting to get more power out of this, would you recommend porting the heads I have now, or starting with different heads for this combo? What would be your recommendation for heads for this?
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Re: 423 SBC combo help

Post by maxracesoftware »

allens :

Thanks Larry, that's a lot of information!

We can hopefully get it optimized as-is, sounds like we may have another weekend at the track this year, and then possibly try some dyno time this winter.

If we're wanting to get more power out of this, would you recommend porting the heads I have now, or starting with different heads for this combo? What would be your recommendation for heads for this?
if its fits within your Budget , i'd go to a good Engine Dyno Shop , and Dyno test/tune what you have now
see what's real TQ and HP and what were RPM points like it ran down the Dragstrip ,
see if you can solve what you have now ?

if its really down on TQ and HP , and it can't be fixed tuning on the Dyno

then most probably will be Cylinder Heads ... get them Ported ... re-Dyno everything again .

We've done something like this many times
especially if its a new Customer who has doubts , we Dyno his engine exactly like he ran down the Dragstrip
then redo everything .. re-Dyno it again , show him the gains , then prove at the Dragstrip with the ET Slip data
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Re: 423 SBC combo help

Post by PRH »

We've done something like this many times
especially if its a new Customer who has doubts , we Dyno his engine exactly like he ran down the Dragstrip
then redo everything .. re-Dyno it again , show him the gains , then prove at the Dragstrip with the ET Slip data
I’m sure that scenario has played out many many times at your shop.
Somewhat handy with a die grinder.
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Re: 423 SBC combo help

Post by prairiehotrodder »

hopefully will have some updates to this story after this weekend.
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Re: 423 SBC combo help

Post by prairiehotrodder »

Bringing this thread back to life. Its an ongoing project. I tubbed the car this winter and it now has 14 x 32 slicks. Its also getting a Holley strip dominator intake in place of the AFR plastic unit which always leaks. Its possible that the plastic intake flexes at the back where the distributor goes through and eventually leaks out the back seal. Not sure but thats the best guess at the moment. We never did get the engine on a dyno because dyno time is hard to get around here. Hopefully we will have the car at the track in August. I'd like to see this car in the high 9's but if you read the thread you will see a long story of trial and error and hard to know why this motor doesn't make the power we had hoped. Some 1 7/8 headers are in the works for it but i highly doubt they will give us the 100 hp we are missing.
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Re: 423 SBC combo help

Post by enigma57 »

Wish you all the best! And I believe you are correct regarding the plastic AFR intake flexing at rear due to distributor being mounted through intake on small block Chevy. You can get away with that using either a cast-iron or well made and correctly machined aluminum intake, but asking plastic to stand up long term to all the forces at play where distributor mounts is just too much.

I have several areas in mind where I believe the initial smallblock Chevy design could (and should have) been better done but was not so as to save a few bucks in production and this is one of them. In my view, it would have been much better to have the distributor mount to a machined surface in the block and add a separate valley cover under the intake (also doing away with the potential oil leaks at 'china walls'). And shaft mounted adjustable rockers, 18 degree canted valve heads, either more (6) tapped holes along perimeter of rocker covers or center-bolt hold-downs for covers.

And as long as I'm just dreaming here...... A high nickle content block casting with wider bore spacing that would support 4.185" bore whilst retaining space for water jacketing allowing free flow of coolant between all cylinders and allowing room for future overbore, more meat cast into block for 4-bolt splayed main caps when HP levels at some point in future might reach the level where they became necessary.

Just dreaming of course,

Harry
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Re: 423 SBC combo help

Post by rustbucket79 »

I’ve done the comparison between our 1 3/4 dyno headers and my personal (Doug’s) 1 7/8 chassis headers, both with 3 1/2 collectors on several 600 to 700 hp engines.
The bigger headers: lose below 5300, pretty much overlay up to 6300, and gain from 5 to 15 numbers above 6300.
There is nothing magical about a slightly larger primary tube unless the current headers are horrible.
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Re: 423 SBC combo help

Post by GARY C »

enigma57 wrote: Sun Jul 18, 2021 12:13 am Wish you all the best! And I believe you are correct regarding the plastic AFR intake flexing at rear due to distributor being mounted through intake on small block Chevy. You can get away with that using either a cast-iron or well made and correctly machined aluminum intake, but asking plastic to stand up long term to all the forces at play where distributor mounts is just too much.

I have several areas in mind where I believe the initial smallblock Chevy design could (and should have) been better done but was not so as to save a few bucks in production and this is one of them. In my view, it would have been much better to have the distributor mount to a machined surface in the block and add a separate valley cover under the intake (also doing away with the potential oil leaks at 'china walls'). And shaft mounted adjustable rockers, 18 degree canted valve heads, either more (6) tapped holes along perimeter of rocker covers or center-bolt hold-downs for covers.

And as long as I'm just dreaming here...... A high nickle content block casting with wider bore spacing that would support 4.185" bore whilst retaining space for water jacketing allowing free flow of coolant between all cylinders and allowing room for future overbore, more meat cast into block for 4-bolt splayed main caps when HP levels at some point in future might reach the level where they became necessary.

Just dreaming of course,

Harry
Why would it flex when it's supported in the block right above the cam gear?
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