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Torque peak SBC

General engine tech -- Drag Racing to Circle Track

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novafornow
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Torque peak SBC

Post by novafornow » Sun May 17, 2020 12:33 pm

I have a 377 sbc that I put together out of used parts. It is running perfect, but I am having a new converter built and am trying to guess at the torque peak. Do not have a dyno near me, so I have to make an educated guess. The basics are as follows: track1 heads that flow 308 with a 2.08 valve, 13:1 compression, 750 carb. Cam is .657 intake, .627 exhaust 260/266 @ .050”. 108 lobe separation installed at 105. Anyone care to guess at torque peak? I am guessing about 5600-5700. I would like the converter to be 400-500 over torque peak.

mag2555
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Re: Torque peak SBC

Post by mag2555 » Sun May 17, 2020 3:30 pm

If there stock track 1 heads which anytime I have started to port then up flowed between 250 to 260 cfm and with there normal minimum port area and your cid I would say 6000 is more like it for peak Torque with that Cam.

steve cowan
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Re: Torque peak SBC

Post by steve cowan » Sun May 17, 2020 3:34 pm

There is 2 different opinions on converter stall, peak torque or peak hp that I have read on the forum here.
I am no expert on the subject but the theory of keeping the power band above peak torque make sense to me in a drag racing application of course opinions will differ but that's fine.
I switched up from a 9" 4200 to a new 8" 5600 converter in my streeter and picked up 3 tenths in the quarter and lost 1.5 mph but it ran quicker from 11.43 to a 11.10 @ 3650 pounds.
My engine at the time only made around 480-490 hp no dyno just slide rule, but my converter guy asked me everything about the entire car setup and the then came up with the 5600 stall and the first thing I said of course was it's to big for the street, his response was if you don't like it send it back and he will set it up how I want it lol.
I only rang him back to thank him for his good work and didn't mention about anything being to big, it drives as well as the 4200 converter, I am in the process of building another 383 and am thinking of a 6000 stall, sorry about the rant but a good converter shop should get you exactly what you require for your application.
steve c

novafornow
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Re: Torque peak SBC

Post by novafornow » Sun May 17, 2020 4:47 pm

mag2555 wrote:
Sun May 17, 2020 3:30 pm
If there stock track 1 heads which anytime I have started to port then up flowed between 250 to 260 cfm and with there normal minimum port area and your cid I would say 6000 is more like it for peak Torque with that Cam.
They have been ported. I was not guessing when I said “flow 308 cfm”. I am confident that I will be happy at 400-500 over peak torque, just not sure where that is. Right now I am looking at 6200 stall

DeezNutz
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Re: Torque peak SBC

Post by DeezNutz » Sun May 17, 2020 8:35 pm

Contact a good converter company, give them your specs and they will get you pretty close. I have used Dice Converters in California - Jeff Paradise, he is a good guy and knows his stuff.

novafornow
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Re: Torque peak SBC

Post by novafornow » Mon May 18, 2020 9:40 am

I am not asking about a converter, i am asking about torque peak. I thought that there may be some that would have a pretty good guess from past experience. Maybe Mike can chime in. I am working with Jeff on this.

BlitzA64
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Re: Torque peak SBC

Post by BlitzA64 » Mon May 18, 2020 12:11 pm

I have my dyno sheet from a similar engine had more intake lift near .700. Torque peak 6000. Hp peak 6900. Pulled to 7600 with only a single digit hp fall off

novafornow
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Re: Torque peak SBC

Post by novafornow » Mon May 18, 2020 12:29 pm

BlitzA64 wrote:
Mon May 18, 2020 12:11 pm
I have my dyno sheet from a similar engine had more intake lift near .700. Torque peak 6000. Hp peak 6900. Pulled to 7600 with only a single digit hp fall off
Thank you for the response. Did your heads flow similar CFM?

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Re: Torque peak SBC

Post by BlitzA64 » Mon May 18, 2020 1:48 pm

yes, not quite as good

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