Dyno results from my sbc 400, feel free to opine

6750 Views 130 Replies 27 Participants Last post by Lew540, 1 mo ago

RickSBC400

Discussion Starter · 2 mo ago

I got around to taking my car to the dyno after doing some significant changes over the last few months. I will list my combo below and then the chart and graph.

SBC 400 stock bore/stroke - world motown block
5.7" rods
mahle flat tops with reliefs for pistons
236/242 hyd roller 111lsa, +3 advance ground in .580 lift both intake/exhaust
johnson hyd roller lifters
afr 220 heads race ready port version
holley strip dominator single plane intake
4 hole hvh 1" spacer 1/2" of it sits recessed in the intake
holley sniper efi and hyperspark ignition
1 3/4 headers

Personally I was expecting more torque, but happy with the horsepower number. I run a water pump, power steering pump and alternator as my accessories and clutch fan. turbo 350 transmission and 12 bolt rear end make up the drive train loss of things. What multiplier would you use to get back to engine numbers at the crank?

Rectangle Slope Plot Parallel Font

Rick

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mr 4 speed

· #2 · 2 mo ago

Nice results, 416 HP and 375 ft./lbs. torque will get it done.
There is no multiplier to get the HP/TQ at the crank.

FWIW, 390 RWHP is good for mid-high 11's @115 MPH with a 3800 lb. race weight A-Body if you can get a1.6 60 ft. time
So 416 HP would theoretically do better.
A time slip will tell even more and show how well the car is "working"

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RickSBC400

Discussion Starter · #3 · 2 mo ago

mr 4 speed said:
Nice results, 416 HP and 375 ft./lbs. torque will get it done.
There is no multiplier to get the HP/TQ at the crank.

FWIW, 390 RWHP is good for mid-high 11's @115 MPH with a 3800 lb. race weight A-Body if you can get a1.6 60 ft. time
So 416 HP would theoretically do better.
A time slip will tell even more and show how well the car is "working"

Thanks I am excited about it and will get it out to the track this year. It has the suspension/traction bars/drag radials so i should efficiently be able to put the power the ground. I race at Bandimere so if that gets me to 12.0s I'd be pretty thrilled.

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blue_69_malibu

· #4 · 2 mo ago (Edited)

Two thoughts, both of which may not be universally accepted:

1) I believe that your combo.....which is a lot like mine....will have 22-25% power loss do to the accessories that you are running. So, 416-375 at the wheels is likely around 530 HP and 480 TQ Gross.
2) Personally, I would have run AFR 195 heads. I think using a 220 sized head and 1 3/4 headers hurt your TQ numbers.

That said, that motor is STRONG. Enjoy it!!!

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blue_69_malibu

· #5 · 2 mo ago

RickSBC400 said:
Thanks I am excited about it and will get it out to the track this year. It has the suspension/traction bars/drag radials so i should efficiently be able to put the power the ground. I race at Bandimere so if that gets me to 12.0s I'd be pretty thrilled.

When Altitude is not in play, that's an easy mid-11 second car or better....if you can hook.

At sea level, I bet you trap close to 120 MPH.

blue_69_malibu

· #6 · 2 mo ago

You're making a lot more power than I am and have a few 11.9x time sleeps.....although I'm hoping for some better ones with the new AFR 195s finally on my motor.
I have to catch the esteemed Mr. 4 Speed and his LS-6.

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mr 4 speed

· #7 · 2 mo ago

blue_69_malibu said:
I have to catch the esteemed Mr. 4 Speed and his LS-6.

You probably wouldn't like racing your car with the stock intake and exhaust manifolds on G70-14 Polyglas tires

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RickSBC400

Discussion Starter · #8 · 2 mo ago

blue_69_malibu said:
Two thoughts, both of which may not be universally accepted:

1) I believe that your combo.....which is a lot like mine....will have 22-25% power loss do to the accessories that you are running. So, 416-375 at the wheels is likely around 530 HP and 480 TQ Gross.
2) Personally, I would have run AFR 195 heads. I think using a 220 sized head and 1 3/4 headers hurt your TQ numbers.

That said, that motor is STRONG. Enjoy it!!!

I think you have valid points. In fact my old heads were old old afr 195s. I just wanted to buy and try these new heads out. i'm going to use the old heads and cam on a sbc 400 my dad has a short block for. I have a rpm air gap i may swap on next year for fun and re dyno it.

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68Chevele

· #9 · 2 mo ago

A 106° LCA would have pumped up the torque along with an Ari Gap IMO. While the strip Dominator is a good intake it does suffer on the low end torque. Either a smaller head or bigger cam would make more power also. Your results showed me one thing as I have some CNC ported AFR 210's here at the shop and they might not make more power with my small cam over my ported Vortec's. Is this 406 a street engine or track engine, also was this a chassis dyno? if so the 410hp is a good number.

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Jesse 496

· #10 · 2 mo ago

Had a 406sbc with afr 195s the port volume could effect power down low you could offset set that with a cam and rpm it or add a duel plane intake like an airgap that should give you more bottom end for cheap if your car is heavy.? My friends 2014 camaro made 403hp rwhp and ran 12.013 at not sure on weight maybe 3700ish with driver if that helps

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blue_69_malibu

· #11 · 2 mo ago

mr 4 speed said:
You probably wouldn't like racing your car with the stock intake and exhaust manifolds on G70-14 Polyglas tires

I didn't say it was apples-to-apples.

Your exhaust has got to be be holding you back compared to headers.
But you're car is SOOO bad a*s and runs so well......it makes for a nice bar to try to chase.....totally out of respect.
It's not competition. It's tons of respect and admiration.

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mr 4 speed

· #12 · 2 mo ago

blue_69_malibu said:
I didn't say it was apples-to-apples.
Your exhaust has got to be be holding you back compared to headers.
But you're car is SOOO bad a*s and runs so well......it makes for a nice bar to try to chase.....totally out of respect.
It's not competition. It's tons of respect and admiration.

Thanks Tony, I really appreciate it. Means a lot.
One of these days, I will lose those exhaust manifolds.I have a nice pair of 1 3/4" primary headers to "test out"
They wouldn't be optimum for my engine but better than manifolds.
Rick, don't mean to hijack your thread.

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RickSBC400

Discussion Starter · #13 · 2 mo ago

68Chevele said:
A 106° LCA would have pumped up the torque along with an Ari Gap IMO. While the strip Dominator is a good intake it does suffer on the low end torque. Either a smaller head or bigger cam would make more power also. Your results showed me one thing as I have some CNC ported AFR 210's here at the shop and they might not make more power with my small cam over my ported Vortec's. Is this 406 a street engine or track engine, also was this a chassis dyno? if so the 410hp is a good number.

it was a dynojet chassis dyno. I was pleased/fine with the horsepower numbers, just thought the torque was a bit low but could be due to the headers and the cam. compression is 11:1.

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RickSBC400

Discussion Starter · #14 · 2 mo ago

mr 4 speed said:
Thanks Tony, I really appreciate it. Means a lot.
One of these days, I will lose those exhaust manifolds.I have a nice pair of 1 3/4" primary headers to "test out"
They wouldn't be optimum for my engine but better than manifolds.
Rick, don't mean to hijack your thread.

Always cool to hear about your car or combo and next phases.

Reactions: 2

RickSBC400

Discussion Starter · #15 · 2 mo ago

Jesse 496 said:
Had a 406sbc with afr 195s the port volume could effect power down low you could offset set that with a cam and rpm it or add a duel plane intake like an airgap that should give you more bottom end for cheap if your car is heavy.? My friends 2014 camaro made 403hp rwhp and ran 12.013 at not sure on weight maybe 3700ish with driver if that helps

I may put an rpm air gap on it next year at around this same time, go thru 2 seasons one with a single plane one with dual plane to give a full go and shake at driving and racing with the setup each way.

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71350SS

· #16 · 2 mo ago (Edited)

The large bores of the 4.155 406 cid just eat those 220 cyl heads up and I believe they're not as affected like the smaller bores of a 355 cid based 383's would be by the 220 heads.
.

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-SS454-

· #17 · 2 mo ago

Nothing wrong with 416 rwhp, though I notice its when the dyno was shutdown. Any reason it wasn't taken past 6200?

What catches my eye is the unusual lack of torque at low RPM. That's very low numbers below 4000 rpm. I wonder if something was up in the tune or is it just that sluggish down low? If this is a street engine, I feel it's going to need a lot of gear.

Side note: why is the dyno graph done on MS Excel?

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mrpaticular

· #18 · 2 mo ago

I think the heads and intake have lost you some but not enough to be replacing on a street engine.
As far as the track goes, you will find out where your weaknesses are. Always a good thing. I think the engine power are just numbers unless the rest of the car and driver are up to the task.
I don't talk hp and tq , just seconds. All talking stops when the green light pops !!

Rick

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RickSBC400

Discussion Starter · #19 · 2 mo ago

-SS454- said:
Nothing wrong with 416 rwhp, though I notice its when the dyno was shutdown. Any reason it wasn't taken past 6200?

What catches my eye is the unusual lack of torque at low RPM. That's very low numbers below 4000 rpm. I wonder if something was up in the tune or is it just that sluggish down low? If this is a street engine, I feel it's going to need a lot of gear.

Side note: why is the dyno graph done on MS Excel?

i think its low on torque too down low, maybe it's the intake manifold and headers. oh well, ill try the dual plane next year. the tune seemed fine AFR was good and timing was good, didn't want to go much more than 34*, as i don't want to run it more than that. oh and i shut the dyno down at 6,200 bc it wasn't going to do much more above there imo maybe 10 more, but i saw what i went there to see and hit the number i wanted to hit for hp, above 400 at the wheels. the torque number i had a feeling no matter what else i did, i wasn't jumping that up a whole ton so i called it quits at that.

I got a graph printout and chart printout but i wanted to put them in excel to track the data lol.

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RickSBC400

Discussion Starter · #20 · 2 mo ago

mrpaticular said:
I think the heads and intake have lost you some but not enough to be replacing on a street engine.
As far as the track goes, you will find out where your weaknesses are. Always a good thing. I think the engine power are just numbers unless the rest of the car and driver are up to the task.
I don't talk hp and tq , just seconds. All talking stops when the green light pops !!
Rick

the old combo had a best time of 12.35 so hoping I beat that. Gears are 3.90s and converter flashed to 4k so it gets up and goes when I ask it to.

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