lunati 401b1

Ok i finally dedided on a cam. I picked the lunati 401b1. this will be going in a 350 with flat top pistons(10:1) iron eagles 215's edlebrock performer rpm with a modded q-jet.the exhaust is open-headers 3in collecters.it will have electric fans also. tranny is a th350 with 3500-3800 stall and there backed up by 410 gears. the car weighs about 3200 pounds. Just wondering what hp/tq i will see and 1/8 and 1/4 mile estimates. it will have 275x60x15 drag radials on a 15x10 wheel. thanks in advance!

Lunati 401b1
247/255 duration
525/540 lift
106 lobe seperation  

Your looking at what I think would be a soggy bottom end power engine with possible high rpm power.

I would say a 4.10 gear is too tall for that cam, its good to 7000 rpm.

I think you may be better with a 4.88 or 5.13.

I also 10:1 compression is too low for the huge duration, I think 11-11.5 would be better suited for that large cam.

Can I ask what kind of rotating assembly are you going to turn this many rpms?

How about post the whole engine combo.  

Your package is looking good until the torque convertor stall speed. If you haven't ordered it yet back it down to 2800 to 3200 stall.

Make sure you use a very good valve spring with that cam. It's coming around very fast @100 degrees LSA.    

Make sure you check valve to piston clearance, even using flat top pistons!!!.........  

2800 rpm stall speed will kill this thing.  It wont be able to 60 foot to save its life and shift recovery wont be where it needs to be either.

The converter you have is close but not large enough either.  But...you have to make some concessions if its going to be a street car also.

For maximum drag strip performance, flash stall speed of the converter ought to be about 200ish rpm HIGHER than your peak torque rpm.

With the way this combo is shaping up peak torque should be closer to 5000rpm.  somewhere between 4500 and 5k at least.  The right converter would stall around 5k and you'd be shifting somewhere around 6500 or so and going thru the traps a little higher than that.  

For a street car, that will be enough converter.  Just make sure its a quality converter with a quality cooler.  I drive around with a 4000 stall speed in a car much heavier than yours.  Its a good 9.5 inch converter made by art car and unless you put the pedal to the metal, it doesnt act like a large converter at all.  It drives around perfectly fine.  I have driven much larger converters around also.  A quality, higher stall converter doesnt have the issues that "most" of the cheapie 300 dollar converters have(but youd be surprised how many good ones there are in the 3 to 400 dollar range but the mail order catalogs dont typically carry any of the good ones).

Dont worry bout the compression either.  Thats a solid flat tappet.  When you consider the faster ramps and figure valve lash into the equation.....the seat duration is very short.  Much shorter than most old school hydraulic flat tappets that folks run with less static compression.

It'll have plenty high cranking compression with that cam and 10:1.  Better than most hydraulic flat tappets folks run.  Seat duration is only 280 degrees.  With an iron head and that small seat duration I wouldnt push the compression any harder.

It will be in the 11's.  If that quadrajet was worked over properly to fit this engine....expect in the 11.6 to 11.7 range at 114 plus mph.  

its a 2bolt main 350 block which is at machine shop right now. bore has been checked and it is still 4in the machinist said it looked good. the heads are the iron eagle 215 with 205/160 valves and valve springs good to 540ish lift. it has stock crank that is 20/20 and stock rods. it will have arp bolts and studs in the bottom end. it will have hpyertanic flat top pistons with 2 valve relief. intake is edelbrock perfromer rpm 1500-6500 .the cam is the lunati 401b1 solid mechanical lift. 1.5 ratio roller rocker arms with hardened pushrods and guideplates. and the carb is the worked qjet. this will be a street/strip car so i was hoping i could get away with the 4.10 gears and 3500-3800 stall.

is there any hp/tq estimates...i know its hard to say with out dyno but just curious

i also have a torker II but from what people have said is my edelbrock rpm will flow better than it will. Hope i answered all your questions.
and for the converter i was getting mixed signals one says go smaller one says go bigger. Thanks for all input!  

Mostly street? or mostly strip?  

Bottom line,,,, 4.10 gears and a large stall converter on the street with a 3 speed automatic,,,, sucks as far as any kind of drive ability is concerned.

Yes you can "get away"  with this combo I just think it will be less than desirable on the street, or mostly street.

I never recommend bigger than .500 lift for a mostly street car simply cause most of the time you are operating under where the cam is designed to run.

In this situation these large runners will work fine with the cam. I just wonder if you will ever wind it high enough to really get the use of them?  
 I agree that the 3500 stall will be fine with this combo, any lower and I think it would be lazy on the hole shot.

I think the performer rpm is a little on the small side for max performance but it will work, I would use a victor, 215cc could make use of it.  

mostly strip. i understand what you are saying about 500 lift on street. the only time it will be driven on street will be weekends and occasionally a friday to school. this is a toy not a daily driver.  

I still think the 4.10 gear is too tall for best time on the strip with the rpm of this engine combo.

you would be doing roughly 100mph at 5200 -5500 rpm  you need to cross the finish line at at least 6000 to get the most out of this engine.
 other wise you may not shift into 3rd gear till right at the finish line.  

Alright...Im gonna knock out a few posts here to get some things across.  first is the converter.

If you and I bought the identical converter....say a 10 inch 3500 rpm stall speed converter, and my car had a big block chevy and the vehicle weighed 3800lbs and your car had a small block chevy and weighed 3400lbs......even though we have the identical converter, it will act VERY different in both of our cars.

There are three types of stall speeds in a converter that serve different functions.  Flash stall, brake stall, and true stall.  Converters react to the load input into them.

Since my car is heavier and we also assume the big block makes more torque in the 3500rpm range.....that converter WILL stall higher in my car than it does your car.  

Flash stall is where you will see the biggest difference between the two, and this is also basically the most important stall speed.

The moral of all this is that you CANNOT buy a converter out of a catalog and expect it to be right.  Different cars with different engines will make converters act differently.  If you want it to be spot on, the only way to get it just right is to call the company that makes the converter you are buying.

A good converter company will ask you a ton of questions about your car and your usage.

Now...here is why it should be(but doesnt need to be) a bigger converter.

I will guarantee you if you called up a good converter company(coan, Edge, ATI, PTC just to name a few good ones) and explained to them you are building a max effort car where maximum ET on the drag strip is important.....all of them will do their best to set you up with a converter that stalls right around, but just slightly after peak torque.

Do enough max effort deals and you will see that trend.  For maximum performance any converter company would want a larger stall speed that hovers around peak torque for a launch rpm.

Now....I realize this is not a max effort build.  You would compromise a little bit for a street car.  And, by using a 3500-3800 converter....you already have compromised.  There is no way the engine you built will make peak torque much below 5000rpm.  Thats not to say that it wont have any torque down low.  that just means peak torque ought to happen somewhere in the mid to high 4000rpm range.

With that in mind....the converter you chose is roughly 1000rpm too small of a stall speed if this were max effort.  Since its not max effort and its a street engine, 1000rpm less than "optimal" is a good compromise.

A 3500 to 3800 converter is a good middle ground between too small and max effort.  Its also not nearly too large for a street driven car.  Would you believe me if I told you there are cars out there logging thousands of street miles, towing trailers behind them to races running 6000rpm and larger stall speeds?  there are and I can show you some proof if you wanna see it

this is why we go back to quality converters.  There is a such thing as a tight and a loose converter.  You can have a tight 3500 conveter and a loose 3500 converter that drive wildly different.  A good high stall speed converter wont act like a high stall speed unless you really hammer on it.  

I dont know who's converter you are using but like I was sayin...my 4000 stall speed converter drives around like a stock converter until I go full throttle.  thats what it was designed to do.  It stays tight for driving at light throttle and cruise but really only stalls up when its fed full throttle power.  

You wouldnt believe me that its a 4000 stall until I cracked it wide open.  Its tighter than much lower stall speed TCI converters I've used for example.

the stall speed number is an arbitrary number.  The design of the converter will greatly effect driveability.  A good one drives good even if its a large converter, which is why I have no problems driving large, and even sometimes seemingly huge stall speeds around.  

As far as your rear gears go...  with a 28 inch tall tire this combo will cross the finish line turning at least 6000 rpm with a 4.11.  If the tuneup is right, this combo easily has the potential to go faster than 110MP.  So...we'll use 110 as our guideline.

If you do the math, at 6000rpm with a 28 inch tall tire and 4.11's you get 121 miles per hour.

BUT....unless this is a transmission with a lockup converter(which yours isnt), there is not a converter on the planet that locks up 100% even after the stall speed.  There is always slippage present.

Around 10% slippage is fairly common for the average converter.  So if you take 121mph and multiply it by 90%(factoring in for 10% slip) you how have roughly 109 MPH.

As we figured..you should easily have the horsepower to go 110 at least with your combo.  And at 6000rpm...you'll ony be going 109.

This combo will turn 6000 rpm plus with the gear thats in it.  I wouldnt change a thing til you drive it some and race it some.  Then you can decide if you want more or less gear.

Part of street driving is personal preference.  A lot of people dont like 4.11's with a 3 speed in a street car.  Me myself?  I have 5.13's in my street car with no overdrive.  I know.  Its a monster gear.  But I personally dont mind it.  Its all you're call as to whether or not you dont like driving it.  

Last but not least....your heads, intake, and valve lift.  I've used that exact head on a 355 chevy that was street driven all the time.  Very similar setup to yours, escept more converter.

It was in a 78 camaro that was actually a little heavier and was bracket raced(driven to and from the track and was number 1 in points).  Its a large head but definitely not too large.  It drove fine and with a smaller hydraulic cam than yours it ran regular 12.60's.  You have a better camshaft and a lot less weight.  You'll be running faster.

Port CC alone doesnt tell you much however.  Neither do flow numbers, so you cant really just look at the CC of the head and make any call as to whether or not its too large.  

Valve lift also influences rpm very little.  Duration is what helps determine how much rpm an engine wants to spin.  Valve lift only helps determine how much air you can move and power you can make at that rpm.

Think of the bbc or ls engines.  Factory 1.7 rockers which provide much higher valve lift than your conventional small block chevy.  Very mild motors can still have plenty of lift.  Im a fan of running as much valve lift as possible with a given duration that you know you need to get the rpm done.

And your intake.  Yep.  Ditch the torquer.  Its not good for anything.  The only other intake Id use is the intake you already have, or a victor junior.

My only gripe with your combo is the hypereutectic pistons.  This build needs a forged piston.  

just a couple more things I wanted to add relating to the converter.  This is some info from ultimate converter concepts(real good guys..they make a heck of a converter).

"The primary thing to remember about torque converter stall speed is that a particular torque converter does not have a "preset from the factory" stall speed but rather its unique design will produce a certain range of stall speeds depending on the amount of load the torque converter is exposed to. This load comes from both, the torque produced by the engine and the resistance of the vehicle to move from rest. For best drag strip results use a converter that stalls close to peak torque. Some people advocate a bit above, others a bit below peak torque RPM. Again, close cooperation with the converter manufacturer is the best approach."

And this info is from Marty Chance of Neal Chance racing converters.  This is concerning how much stall speed is needed for a particular app

"first of all the answer varies according to your goal (peak performance or consistancy)
heads up racers will shift at a higher rpm to increase the recovery time of the shift where a bracket application will shift much sooner to increase consistancy


second it varies with torque curve (stock headed 440 mopar vs. short stroke high rpm big head sbc)
the more low rpm torque you make the more a short shift you can get by with, but even the low torque short stroke motors can short shift if the converter stall is high enough . Most motors have about 1000 rpm spread between peak HP and peak TQ so as a rule of thumb you should start out with shifting at peak HP and let the rpm drop on shift to peak TQ then you can play around with short shifting or stretching the shift out higher and see what works best for your specific combo.

Hope this helps some, Marty Chance"

You'll note that The UCC guys explain stall speed should be right around peak torque.  Some say a bit before or a bit after(were talking about a couple hundred rpm swing in either direction).

Marty explains why.  Depending on if your bracket racing, or heads up(max effort) will dictate whether the converter stall speed might fall before or after peak torque.

We're not just worried about launch rpm.  Shift recovery matters also.  If its a heads up max effort deal, you're going to ride the rpm out as far as you can.  You rarely even see peak torque.  Its all rpm all the time.  this is when you'll often see the stall speed higher than peak torque for max performance.  It lets you launch in the strongest part of the power band and it ensures that when you shift....rpm drop will be minimal and you will never drop under peak torque being that the stall speed is higher than peak torque.  All good things for a max effort car.

For a bracket car that might be shifted much sooner, you sometimes can get away with a lesser converter.  Lots of factors at play here.

Either way stall speed always references peak torque when talking about the "best" converter.  You're a good thousand rpms away from peak torque with your small speed.  This is why I say do not go smaller.  

The only way Id go smaller is if you drive it and dont like it.  But based on all this info, going smaller will not make the car go faster. Thats the one thing that wont happen.  

thanks for taking all the time to reply! i havent got a converter  yet but you got me leaning towards a 4000. i will look at all the brands you have suggested and debate on them.

would a 26" tire help the 411 or will 28 be alrite?  

Id stick with 28.  I wouldnt make any rash decisions til you run it.  Id want the 28 for street driving, and if you do race it...the 28 will hook easier than the 26.  If you wanted to spin harder thru the traps Id prefer to add more gear rather than remove tire height(because of the traction advantage).  But again I think its pretty close so I wouldnt change anything til you drive and decide.

Here is what I suggest.  Call up one of the good converter companies and talk to them about your combo.  Have as much details handy as possible.  Engine displacement, heads, compression, gears, tire height, camshaft specs(as detailed as you can find) vehicle weight(and if you havent weighed it at least look at what your vehicle should weight....assuming its not been heavily changed you'll be close on weight)

Edge makes a very good product for a good price.  TSI(which is transmission specialties), PTC, and coan is another Id call on the phone.

All of these guys are more than capable of providing a great street/strip converter.

Last but not least, be honest with the folks about how you plan to use the car.  Let them know your driving habbits as well as how often you will race. I too would not have a problem with putting something in that stalls around 4000rpm.....but considering how picky torque converters are about the application they are in..you definitely want them to tell you which one of their products you want.  

alrite will do. i seen on ebay the freakshow converter. they were 320 bucks amd they said they do all custom orders. are they worth looking into?