10.4:1 406sbc

AFR 1054 heads
http://m.summitracing.com/parts/afr-1054

Victor Jr intake
http://www.summitracing.com/parts/ed...FcgWMgod9HAAjQ

Quickfuel SS-850 carb
80 front jet, 86 rear jets. 3.5 powervalve, .37 squirter. Initial timing 18deg, black bushing with medium blue medium silver spring on MSD Pro Billitt distributor.
Vaccum 5.5 at best in gear, mixture screws all equal, just over 1 full turn out.

Howards camshaft 180345-10
http://www.skipwhiteperformance.com/...Item=180345-10

The air fuel mixture measures great, but this combo should make way more powe than this!??
My old 350 made 308rwhp. Am I missing something easy?

 

What RPM is the motor making that power at? That is a huge cam by any standard. You would need to rev to 7000 to take full advantage.

 

The dyno didnt provide that information on my sheet, dont know why. They pulled it to 6500

 

Also, whats with that huge spike at the end of the run? Torque shot up to about 343

 

Isn't 13.5 AFR a little rich? I thought you wanted to keep it around 12.5 for optimal performance

 

I dont think the cam is that much of a killer considering the 6500 RPM redline you took it to, but it is pretty big. The intake seems right, the heads are close. Something's not right.
Full combo including exhaust needed etc etc needed.

Also run it with RPM next time.

 

You have the distributor set up right and 36 degrees total is in the realm of where it should be.
Try double checking tdc with a piston stop. Your timing may be off. I have seen some of the inexpensive balancers be as far as 9 degrees off brand new out of the box. So if you bought one of the cheapos from skip white it could be the problem.
Just a side not on the distributor. put a 10 degree bushing in. It will give you roughly 26 degrees at idle which will improve idle quality and vacuum and off idle response and power.
http://www.ebay.com/itm/MSD-10-degree-advance-bushing-/290985683959?pt=Motors_Car_Truck_Parts_Accessories&hash=item43c0192bf7&vxp=mtr
That is just something the dyno does sometimes. It has to do with the rpm pickup filtering. It is not actually the engine making that spike.

No it is lean, but I think that is what you meant cause 12.5 is a good safe number to shoot for. I usually try for around 12.8.

That cam in a 406 should make peak in the low 6000's.

I funny exhaust will definitely cause the power loss. I have seen a mild 454 pick up over 40 to the wheels just changing out the crappy exhaust it had.

Also try doing a compression test. You may have a funny cylinder, but I would look at checking tdc first.

 

13.5 is more on the leaner side of 12.5. I dont disagree with you regarding 12.5 being best, the dyno shop said ideally thats where I needed to be. I dont know why they didnt incorporate rpms in the run. Im currently in touch with them to get the info.

 

They might not have hooked up the tach signal to the dyno which is why it made that spike at the end.

 

I'll check on that Balancer being a potential cause. Being that it came from Skip White that is a possibility. My installer & I did an extensive investigation on TDC prior to installing the heads, so I am 99% confident that is okay.

I did not do a compression check, I may have to consider that.

Exhaust: I have short tube SLP Headers. 1-5/8" tubes. 2 into 1 exhaust, 3-1/4 pipe into 40 series Flow master. Single in-dual out.

One other thing is that I have 1.6 ratio rockers. The 1.5 ratio roller rockers wouldn't clear the springs that came with the heads. I had to go to 1.6's, thus making the lift .603/.618

I was hoping not too much lift??

 

That was another thing...regarding the tach. I told the guy not to take it past 6500, so he quit when my tach (in the car) said 6500. The tach on the dyno said only 5400.

So he went off the tach on the dyno, when it hit 6500 he stopped. I don't know what the car's tach said then, was it pinned? My wire is connected to my MSD6AL box. I'm not sure where Dyno's get their rpm readings from.

 

Could that lift be creating valve float and costing power?

 

That could be part of the reason for the low hp reading. The dyno uses tach signal to calculate numbers.
Does the car feel slow? Or it seems fine but just didn't make a high hp number?
Also high stall loose or cheap converts will cause really low readings on a dyno.

If it was floating the hp line would fall off really fast after peak hp.

 

Picture of my "Desktop Dyno" software I had when I began my motor swap. This is what I expected....

I have a Midwest Engineering 2800 Stall. Probably too low, but also 4.10 gears.

It seems way faster than my 350 did with 308 rwhp. Before any tuning to this 406 I ran a 12.9 @ 106. My 350 could barely do 13.4.

 

Something isn't right. With that cam and heads you should be going faster than 106.
2800 is way to low. Howards recommends minimum 3500 on their website.

btw desktop dyno is in engine hp not wheel hp. There is a huge difference.

 

That's a lot of lift. With the springs did you check coil bind with those rocker arms and cam lift?
Timing is another factor that for sure needs to be checked. Also... What dyno did you use? How credible is the operator/tuner?

Nother thing... I personally think that exhaust is too small. I would have gone 1 3/4" long tubes, big fat 2 1/2" y-pipe into 3-3.5" tubing. "Your running a 406"
So you are losing some power there.

Honestly, if it feels good then thats the ticket. If it's quicker and the dyno was the same... you need to think about that. If it's dyno numbers you want, get a second opinion.

 

Springs were okay, no bind. Timing is as close to okay as I can possibly get it. 18 initial, 36 total based on the springs & bushings used with the MSD Pro-Billit distributor.

This dyno run I post about was from somewhere other than where I got my 350 dyno'd. I don't know the credibility of the dyno-guys because I've never worked with them before. The first two pulls they did I KNEW something was wrong when it pulled just over 200hp, they did the pull in 2nd gear both times. They did the 3rd pull in Third Gear, where I got the 309/343#'s

I tried to factor in the "Loss" of power through the drivetrain, I certainly didn't expect 550 at the wheels. I was shooting for 400ish at wheels based on the dynojet software I posted earlier. My ideal 1/4 mile will be low 12's. Dipping into the 11's would be too much for me, primarily because I street drive the car 99 times to 1 time at the track. That and I don't want to put in a roll cage

 

I highly doubt you will get over 400 unless you have a tight converter and efficient trans.
I did my friends 383 in a malibu that put down 378 on a dynojet and it runs 11.2 in the 1/4. Automatics put down much lower numbers than manual trans cars especially with high stall converters.
Also you can't compare dyno numbers from wto different shops. Especially if they have different brand dynos. The hp numbers are really just for reference when tuning and a rough idea of the power it is actually making.

Now the dyno operators did not have a clue what they were doing if the pulled it in 2nd gear. You always dyno in your 1:1 gear or the closest to it.

If you want to know how much power you are actually making use your 1/4 mph and car weight.
http://www.wallaceracing.com/et-hp-mph.php

And it should be making much more power than only running 12.9 at 106. So there is something not right.

 

I'm not all TOO familiar with stall converters at all. But on that subject I have a "lock-up Switch" where the converter won't ever lock up until I flip the switch. I usually drive with it unlocked, until after I'm cruising at 70 or better (3200rpms). So I never really feel any "Bogging" of the engine.

 

I already have records of my car itself weighing 3780 from my first dyno with my 350. Using that weight, plus me & gas I estimate for example 4000Lbs.

Based on my cars weight including me & gas, (4000Lbs) and my already proven ET of 12.9 I should have been 368 hp.

Based on my cars weight including me & gas, (4000Lbs) and my already proven MPH of 106 I should have 391 hp

 

always use mph. Et is to dependent on traction and launch.
391 is about right for 309 hp on a dynojet. 20% diference is a rough estimate for the difference of an automatic car on a dynojet to engine hp.
391 - 20% is 312.8

Now with those heads and cam you should be making much more than 391hp.

like I said before the best place to start is to do a compression test on all cylinders and double check tdc to start with.

 

Thats a really heavy car, good lord. I dont think 391hp is ridiculously low. But I would trust that number a lot farther than a synthetic estimated dyno number that is calculated based off of a bunch of assumptions.

I've never been able to figure out whether that trap speed + weight hp figure is rwhp or flywheel horsepower. Allegedly it's flywheel hp and that's what I've always considered it to be, but some of the numbers get a little weird when you play with them and go backwards so I'm not positive. Probably varies.

Do you know what your quench distance is?

 

This combo should be well over 400 whp with a locked converter on most dynojets.

If the 210 heads have 8019 springs you shouldnt have any valvetrain issues. So the main thing i can see is exhaust being too small and tune being off. Try richening wot up to see what it does. Verify timing, try 34-36 deg. Correct dyno issues with tach signal and rpm values. It should pick up. Also try without air filter. I really think this setup needs 1 3/4 shorties at very minimum and 3.5" single exhaust with a straight thru muffler

 

This is all good stuff to know, I am going to tinker with things here over the next couple of weeks, hopefully I'll get a solution & let you know what I come up with.

What do you mean by quench distance? On the head gaskets?

 

It's flywheel hp. It's not 100% correct hp number, but it's generally pretty close and will give you a good idea where you are.

Quench is the piston to deck clearance plus the compressed head gasket thickness.
So if the piston to deck is .015 and the gasket is .35 the your quench is .050. Usually try and shoot for between .035 and.045.

 

I had piston to deck clearance of .002 and crushed gasket .035 I want to say.

 

3 things...

1) the dyno operator should have used the tach on his dyno & not the car's. did you install a tach adapter with your MSD? if not, don't trust your tach, it will be off.

2) 13.5 is a bit lean for WOT, especially with a carb. You paid for dyno time that should have included tuning..


3) unless you have solid lifters a 406 will not need to rev past 6000-6500.

That being said a dual plane Performer RPM air gap manifold is a MUCH better choice than the single plane Victor JR. which is meant for a higher revving application
(6500+)

 

The cam seems OK for the application.

Did you change the torque converter? (higher stall speed) a mis-matched converter will kill some power.

A 406 will want 3.5" collector pipe 4.0" better if you plan to make more power. Anything smaller than 3.5" will be restrictive and lose power.

Check out Mufflex exhaust...

http://www.mufflex-performance.com/

IMHO they make the best aftermarket exhaust kits for the f-body.

I bought the 4" system with off-road y-pipe to connect to hooker super comp headers.
When I had my 383.

 

Maybe not need to but they certainly can. With modern hyd roller profiles, lifters, and springs available, 7k rpm can be done, some even higher. The killer is valvetrain weight. Heavy valves are hard to control especially with aggressive cam lobes but good thing here is AFR uses 8mm valve stems and also hollow stem valves in some heads. They are lighter than typical sbc valves so you get added control. Combine a small diameter stiff double spring and titanium retainers you can spin hyd rollers up very high. Lsx do 7500 all the time but feature light valvetrain and bigger cam cores to help control things.

But for all out power over 6500, solids will take it

His howards grind should go mid 6000's

 

Actually I was referring to the 406's Rod / Stroke ratio. These are not hi-revving motors by design. They simply do not have to rev that high to make power. Careful attention needs to be paid with intake manifold selection, a dual plane is a better choice for this motor.

 

Well we dont know what his rod length is. Stock 400 rods are short, but a 6" rod setup can rev plenty fine. Similar ratio to a 350 at that point

 

Why is that?

 

I just realized that with my 350 I had a 58 millimeter throttle body with 1000 CFM and a mini Ram Intake System. With that being said I went bigger cubic inches but smaller CFM rating on my intake. I guess i have a place to start. .

 

Dry air flow number don't mean much,when comparing EFI to a carb.

actual cfm is determined by injector sizing and fuel mapping..


Basic rules of thumb for intake manifolds.

Dual plane = low RPM TQ & HP

Single plane = High RPM TQ & HP

A 406 is not a high-revving motor so a dual plane intake is a better choice because you will not "see" the RPM range needed to really use a single plane to it's potential.

On my 383 we made 465 HP @ 5800 RPM and 472 lb ft TQ @ 3500 at the flywheel... .80 correction factor for chassis dyno ~ 372 HP

Intake manifold? Edelbrock Performer RPM with Air Gap. (dual plane)
Cam shaft very similar to yours. but it was a Comp Cams.
Dart Iron Eagle heads 215 CC runners.
Torque converter: TCI super street fighter advertised stall speed 2000-2500

The only difference between a 383 and a 406 is the bore size.
The stroke is the same, both combos use 6" rods.


My 421 I have a Brodix single plane intake.. but this is a max effort drag engine that makes 680 HP @ 6800 RPM

 

http://www.enginelabs.com/engine-tec...or-dual-plane/


for your reference.

The ideal RPM range for the Victor series intakes is 3500- 8500+ RPM !!

you will never see this range with a 406... even a purpose built drag engine the max RPM would be limited to 6000-6500.

You would be much better off with a Performer RPM Air GAP Idle - 6500.

 

I am on the other side of the fence. Your OP says its carbed and you are staying with a carb correct?

With your heads and cam you will see over 6000 rpm and that point will benefit in a vic jr.

The efi single plane advertised rpm range is complete bs. I run it. It makes power everywhere regardless of the setup. If heads cam are set to make power to 5500, the single plane makes power there. If heads cam are set to make power to 7000 rpm, single plane will support it if not a restriction to the heads at that point. Ported intake helps

Out the box dual planes i feel will restrict the 210 heads. If you ported the intake heavily it be abit better but your cam is large enough to see benefits of a sp above 6000 rpm. I dont think you will lose any/much low end as afr heads are fast velocity heads. Cam should have 3600 stall anyway. Just my opinion.
It will make good power with a ported dual plane but i think a faster car can be made out of the single

Again a 400 isnt always a truck motor. You can turn them 8k rpms with strong internals. No different than a 355 or 383 with 6" rods

 

While I agree that I would have put a performer rpm on it. It would be much nicer to drive around and only cost a few hp up top if any and make more torque down low which can't hurt especially with only a 2800 stall converter.
That is definitely not what is causing his problem which I think has been forgotten by talking about intakes and if a 406 can rev.

 

yea actually the more I think about it a performer rpm is a little small for 210 eliminator heads for flow. Will probably cost some hp up top. But it depends on weather u want max hp or a more drivable street engine.
And yea like Orr89RocZ said a 400 can rev just like any other sbc with 6" rods.

 

Exactly. 2800 stall and 243 deg cam doesnt jive. Its driveable sure, but torque peak doesnt hit until mid 4000's on that cam. I got a 246 hyd roller in mine with larger heads and i dont start to make power til 3800-4000, but its plenty powerful down below that. But you can tell by the fuel curve its really coming into its power band by 4000, at same time turbos are in full swing. I run 4000 stall for that reason but would run mid 3000's if an all motor street car.

So if you wanted low end and low stall, change cam 10 degs smaller. Else leave alone and add 1000 rpm stall.

But this is all off topic. The low numbers posted are not caused by intake or stall differences. Something else is amuck

 

To the OP, I agree with this I have a 400 with 210s and while I've switched to a multi-port EFI the original intention was a Victor Jnr and to pull 7000. This is a combo that is used quite successfully around here.

 

It's not the intake. Cam and intake seem good. Don't forget the larger motor can also bring that single plane powerband down some. Same with a cam. Ie, a victor on a 305 is more than a victor on a large displacement small block. (I consider a 406 to be larger than your avg. 350/383.)

Seriously you need some investigative dyno runs after an exhaust change. If all seems to run good ATM. .... IMO

 

The exhaust may be choking you a bit, but I think the big issue is the afr. That is pretty lean for wot. I was tuning my car and with the initial tune my car was at 13.2. I added fuel and brought it down to 12.6-12.7. I could feel a big difference in how the car pulled. Was the cam installed straight up? With that cam it should have a little lope at idle, but should pull decent vac with the cubes you have. Is that 5.5" of vac? The other thing is try a bigger carb, I am thinking an 850 may be limiting you as well. It also looks like you have a fairly large pump shot, maybe tune that back a hair as well.

 

I think you have a classic case of the tuning aspects of the motor being off (5 or 10hp here and there), along with a slight mismatch of components.

I'm referring to the timing, exhaust size and design, coolant temperature, carb tuining, and other things. As an example, I picked up about 40hp on my 350 by tuning the carb with an a/f gauge to 13:1, upped coolant temp to 200 degrees, and swapping out a 3" cat back with a 3.5" one - timing was on the money, so that was left as is. Moving from 355hp to 395 with no internal changes is a testament to how much tuning can leave on the table.

About 20 years ago, I worked with a buddy to put together a 406 for his IROC that was destined for road racing. Ended up making 514hp at 5800 and 507lb-ft at 4100 and had a ruler flat TQ curve on the engine dyno. All it took was a 6" rod, 9.5 compression, AFR 195cc heads, hydraulic roller (230/240 split), long tube headers, and a dual 2.5" exhaust (no one made a 4" back then). I ran the car at Englishtown where it put up an 11.7 at 122mph on street tires with 3.08 gearing. A few years later the motor was pulled out, rebuilt, and with a solid roller and 215cc heads it ended up making 580hp at a still low 6300rpm - so a 406 done right can make the power and stay together.

 

4.125" bore + sized 400" and up motors need alot of airflow. They consume alot. Just think of the 396-427 big blocks, how large their heads and intakes are and still very torquey under 6500 rpm. Feed the beast. I think people under cam and under head alot of these motors even on the street, however i feel this combo is a nice street combo, just needs right tweaks. 195's on a 355 are quite popular. 220's on a 400 isnt to far off the same. After seeing how well my low comp 400 runs with a fairly big cam and what i thought were huge heads, i am starting to realize its hard to under head and over cam a 400 plus inch sbc

 

I would have went slgihtly bigger on the heads for a 400 but at the same time this should have been making much more power with these heads. Like mentioned before, tuning in smaller things can end up as one big gain. I'd also go to another dyno after these changes are made, it doesn't seem like these guys knew what they were doing.

 

Great discussion! I helped him build this motor and can say that the info here is great. The initial run we did @ 12.9 and 106 was without a tune at all. No AFR, cheap vacuum advance distributor, overall timing set somewhere around 34, and the car fell on it's face before the finish line.
Since then we changed distributor, added a AFR gauge, tuned the carb with what he listed and was running 12.4-12.7 WOT from 60 to 110 MPH when reading from AEM wideband gauge welded in after headers. Car feels like a beast when running higher RPMs! Pulled hard all the way. Why a discrepancy between AFR readings I don't know.
RPM's seem to be off somehow as well, someone else hooked the factory tach to the 6AL, I assume the dyno did a pick up on a plug wire. Something seems fishy there.
Some long headers and exhaust rework could be in order, high RPMs require alot of air to be moved through.
As for the torque converter, how would a higher stall affect dyno numbers? I agree from a track performance stand point to go higher, just don't see it affecting dyno numbers.
Bottom line is I'd like to see some more track time, as well as a dyno that can show me some RPM/HP/Torque readings, not just MPH.

 

Higher stall may show more slip or have a different torque multiplier and skew the numbers. Hard to say but a unlocked converter will dyno less than a locked one. Now some manufacturers will say not to lock the converter under wot so check. Mine ran fine locked, using edge racing converters. Can show 10-30 hp difference maybe more depending on combination.

Does car have cats? There can be air fuel changes between post cat and precat. But then again i have seen half point difference in header bungs vs tail pipe widebands so hard to say which is right. Thats why start rich and lean out slowly til you see no power gain. Leave richest setting in that gave max power or just below max as some dynos dont load a car as hard as the street/track. Some tunes go leaner off the dyno so try leavin it fat and do a street pull. Retune at the track. Give car what it wants but if car is as heavy as you say, which seems way heavy for a 3rd gen, and 106 mph was untuned, it sounds like its really making alot more power and the dyno was probably off.

Dynos are tools and not the final word to the true performance level of the car. Keep getting slips from the track, dial it in there

And next time trust your tach and ask for a rpm readout instead of mph. Its just a quick change of graph axis units

 

Orr89RocZ basically summed it up for converters on a dyno. The looser they are the lower the number. Thats why I had a malibu only put down 378 and it runs 11.2, big converter.
The exhaust could definitely be holding you back, but I would still double check tdc making sue 0 is actually 0. Then check the plugs to make sure they all look the same and or a compression check. You could have a vacuum leak at the intake underneath on one or two cylinders and never even know. Also a miss adjusted rocker could really screw things up and any of those things will also screw with the afr readings.

 

I hope you are referring to a non-catalyst tailpipe sample, (which I'm sure you are) as there are always changes before and after. Not only that but any car with a y-pipe should be tuned at the collector IMO. This gives each bank its own separate data for optimal tuning. This is also how the ECU does its calculations... with OBD II cars having 1 or 2 extra just for catalyst efficiency monitoring (which we obviously don't have).... Point being... I wouldnt trust a downstream tailpipe reading on a y-piped exhaust system. So I hope the OP is tuning at the collector.

 

Still seems short on power considering my Corvette traps 106 mph with a hydraulic flat tappet cammed vortec head 9:1 305 under the hood.