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423 SBC prediction

General engine tech -- Drag Racing to Circle Track

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prairiehotrodder
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423 SBC prediction

Post by prairiehotrodder » Wed Jul 24, 2019 11:14 am

I've talked about this motor before, its just about done and will likely be raced this weekend. What kind of power and times do you guess ?

Dart little M block. 4.165 bore, 3.875 stroke
AFR CNC 227 heads with T&D shaft 1.5 rockers
13.27 CR on av gas
AFR titan composite single plain intake with QFT 1050 carb (4150 base)
Moroso power pan (the best one with the side kickouts)
comp TK solid roller cam 12-863-9 263 / 272 .648 / .645 108 LSA installed at 106


Most of the parts were in a 383 with 11.1 CR and an 850 carb and ran 10.60's in a 78 lemans with a 5500 stall and 4.56 gears at 3100 pounds. In that combo the cam was in at 110 to give adequate PV clearance with the flat top pistons that were not right for the 60/40 heads.
Brian

The plan was originally to build a 427 (4 x 4.125) but the 423 is what showed up (long story)
The Word of God is quick and powerfull
www.therocketshop.blogspot.com

Elroy
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Re: 423 SBC prediction

Post by Elroy » Wed Jul 24, 2019 11:23 am

640-660

amc fan
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Re: 423 SBC prediction

Post by amc fan » Wed Jul 24, 2019 12:15 pm

600-625@6600

novafornow
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Re: 423 SBC prediction

Post by novafornow » Wed Jul 24, 2019 2:38 pm

agree with above. Looks to be head limited.

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CamKing
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Re: 423 SBC prediction

Post by CamKing » Wed Jul 24, 2019 3:01 pm

645hp @ 6,700rpm

Put some 1.65 or 1.7 rockers on it, and you'll be close to 670hp
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paulzig
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Re: 423 SBC prediction

Post by paulzig » Wed Jul 24, 2019 5:11 pm

655@6500RPM

9.8-9.9 @ 137-138mph

Steve K
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Re: 423 SBC prediction

Post by Steve K » Wed Jul 24, 2019 8:18 pm

My 427 SBC has the same cam, AFR 210's, 11:1 compression and a tunnel ram with dual carbs, 1.6 rockers and other junk that cost a lot. It did 660 hp and 600 tq on the dyno. I will say though that I didn't have the confidence in the dyno operator as it wasn't the guy I usually use but we did do the number. Engine feels like its got all of that so it might be accurate. You'd be in that range with your engine. Feel free to pm me and I can fill you in. I'm in Regina.
79 Cmaro, 427 sbc, Tunnel Ram Dual Quad with Eddy carbs, AFR 210 Race Ready heads, 263-272 @.50 Comp solid roller cam, 4.10's and a faceplated Tremec TKO 600.
65 Beaumont 406 tunnel ram faceplated TKO600

Gregory
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Re: 423 SBC prediction

Post by Gregory » Wed Jul 24, 2019 9:12 pm

Go to www.performancetrends.com and download their Engine Analyzer Pro (it’s free for ten days) and carefully enter
your data and you will get your answer. You’ll also be able to move things around and see how it changes the output My 408 SBC( 600-615HP) on my dyno was “very” close to the Engine Analyzer Pro prediction - good data in good data out.
I see posts all the time asking “what do you think it will make...” The down load is free - what am I missing?

8989
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Re: 423 SBC prediction

Post by 8989 » Wed Jul 24, 2019 10:13 pm

650 @ 6900. I just did my 421 with the same exact head and titanium retainers and it made
702@ 7000rpm
685@ 7500 and still made 665@8000. Those heads are pretty nice. Mine is a dry sump though

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Re: 423 SBC prediction

Post by Curtis Z » Sat Jul 27, 2019 8:31 pm

Gregory wrote:
Wed Jul 24, 2019 9:12 pm
Go to www.performancetrends.com and download their Engine Analyzer Pro (it’s free for ten days) and carefully enter
your data and you will get your answer. You’ll also be able to move things around and see how it changes the output My 408 SBC( 600-615HP) on my dyno was “very” close to the Engine Analyzer Pro prediction - good data in good data out.
I see posts all the time asking “what do you think it will make...” The down load is free - what am I missing?
Amen

prairiehotrodder
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Re: 423 SBC prediction

Post by prairiehotrodder » Sun Jul 28, 2019 10:11 pm

picked up a tenth. I'm sure there is a cork in the system that just needs to be found.

the new combo gained 2 points of CR,
40 cubic inches
200 cfm more carb

and what ? 20 hp ?
The Word of God is quick and powerfull
www.therocketshop.blogspot.com

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BrazilianZ28Camaro
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Re: 423 SBC prediction

Post by BrazilianZ28Camaro » Sun Jul 28, 2019 10:50 pm

prairiehotrodder wrote:
Sun Jul 28, 2019 10:11 pm
picked up a tenth. I'm sure there is a cork in the system that just needs to be found.

the new combo gained 2 points of CR,
40 cubic inches
200 cfm more carb

and what ? 20 hp ?
I run a very similar engine combo besides I have a Victor ram and two 750s, MFT cam and Standard studed rockers.

My best ET is 6.32@111mph in the eigth mile wich is all we're allowed to run overhere in Brazil. Should equals to 9.8x in the quarter.

My '71 Z28 Weight 3300lbs, runs with a TH350 and 4500 stall converter. 430 gears and 29x10.5 Hoosiers.Stock suspension with caltracs.Never dynoed the motor but I'll guestimate close to 700 HP.

I'm pretty sure your missing something with the new setup.

Can you give us a complete description of your car, transmission, fuel system, exaust system,etc?
'71 Z28 street strip car
Pump gas All motor SBC 427
3308 lbs-29x10.5 Hoosiers
NEW BEST ET
1.40 60' / 4.05 330' / 6.32@111.25mph

https://www.youtube.com/watch?v=99p13UK ... ture=share

GARY C
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Re: 423 SBC prediction

Post by GARY C » Sun Jul 28, 2019 11:19 pm

prairiehotrodder wrote:
Wed Jul 24, 2019 11:14 am
I've talked about this motor before, its just about done and will likely be raced this weekend. What kind of power and times do you guess ?

Dart little M block. 4.165 bore, 3.875 stroke
AFR CNC 227 heads with T&D shaft 1.5 rockers
13.27 CR on av gas
AFR titan composite single plain intake with QFT 1050 carb (4150 base)
Moroso power pan (the best one with the side kickouts)
comp TK solid roller cam 12-863-9 263 / 272 .648 / .645 108 LSA installed at 106


Most of the parts were in a 383 with 11.1 CR and an 850 carb and ran 10.60's in a 78 lemans with a 5500 stall and 4.56 gears at 3100 pounds. In that combo the cam was in at 110 to give adequate PV clearance with the flat top pistons that were not right for the 60/40 heads.
Brian

The plan was originally to build a 427 (4 x 4.125) but the 423 is what showed up (long story)
I don't think the AFR 227 head is what is needed for that CI, the set I tested for a 421 only flowed about 309 CFM and the engine probably made 625 to 650, I would want in excess of .700 lift on the intake to try to get all i could from those heads.
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

BigBro74
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Re: 423 SBC prediction

Post by BigBro74 » Sun Jul 28, 2019 11:38 pm

I agree with Diego- something missing. If I had to choose an easy thing to try it would be to use an actual race fuel.
I have never used av gas- I know it has the octane u need, and I know it is probably easier/less expensive for you but if you are turning it pretty hard it may just work better. Could u just get something like CAM 2 up there To try? Maybe I’m out to lunch on this - if so- please disregard ...
You will find something if you work at it—
Jason

BTW- what were the mph? Same? Rpms through the same?

GARY C
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Re: 423 SBC prediction

Post by GARY C » Sun Jul 28, 2019 11:48 pm

BigBro74 wrote:
Sun Jul 28, 2019 11:38 pm
I agree with Diego- something missing. If I had to choose an easy thing to try it would be to use an actual race fuel.
I have never used av gas- I know it has the octane u need, and I know it is probably easier/less expensive for you but if you are turning it pretty hard it may just work better. Could u just get something like CAM 2 up there To try? Maybe I’m out to lunch on this - if so- please disregard ...
You will find something if you work at it—
Jason
Not sure that 101 low lead is enough for 13.2 compression, VP110 is border line at 13.5, all the circle track guys that buy fuel from me for their 420+ inch engine either run 112 or 114.
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!

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