About how streetable would a 406 be with a 700r4. Specs are as follows:
406 shortblock, blueprinted, computer balanced, hypereutectic speed pro 9.5:1
Lunati single pattern 230* @ .050 and .480" lift (flat tappet hydraulic)
Vortec heads, machined for higher lift springs.
Performer RPM Air-gap intake, 750cfm holley dp, and hedman 1 5/8 shorty headers (coated)
The engine is said to make 525ft/lbs @ 3,600 rpm and 427hp @ 5,000 rpm in the August 2003 edition of Chevy High Performance

The 700r4 will be completly rebuilt with a Pro Built kit and Transgo shift kit. I am told it will hold the torque. I will have 3.73 gears and a Zexel-Torsen heavy duty posi unit. The rearend will also have new axles and a rearend brace.

Will this engine get decent mileage (about 12 mpg)??? Is there an way to get better street manners out of it with a different cam or other parts??

Thanks for any input for guys might have!!

 

it will be very tame, seems different from most 406 builds I've seen (what I've seen is 11:1 comp or higher and .550" lift or higher with a cam that has such a ****ty idle it sounds like it's gonna stall out at any moment when idling) but hey' you'll have better efficiency with a TPI unit on that particular 406 build with 20 mpg and some monster torque. but if that's what you want go for it

 

I would go tpi but carb is cheaper. And considering my near future budget, most going to gas, insurance (I'm only 17 and already wrecked one camaro ), and some play money!! And by play money I mean money going into the '82 t/a I'm going to get from my friends brother. The engine and rearend won't come until next summer (sell a pig at fair = approx. $1500!!) but the tranny will be soon because he blew it up.

 

That 406 sunds to be very streetable. I would just plug it in and go.

 

I have a 408 SBC in a '91 Firebird. Specs are as follows:
9.6:1 CR, reworked GM 997 castings w\ 2.02/1.6 valves, Comp Cams 286H Magnum (236 @ .050", .490" lift), Weiand Stealth intake manifold, Holley 750 DP, Hooker SC 1 3/4" long tube headers.

As you can see, my specs are very similiar to what you listed and I consider my car to be very streetable. It definately has a rough idle, but still pulls 15 psi vacuum at idle (1000 RPM in my case).

You will definately want to change your rear drive ratio when you have the means to do so. I went with 3.73:1 and am very happy with the choice. My car is a 5-speed (stock T-5 for now, knock on wood) and came with a 3.08 rearend. It ran alright with the stock rearend but if you have a factory automatic trans car, your ratio may be stretching it a bit with that cam selection.

Another thing I would suggest is having your radiator (assuming it is a stock 2-core) re-cored with 3 rows. Some say it is unneccessary, provided your heads have been drilled for proper cooling (2 holes drilled into the water jackets), but I wanted to be safe.

As far as gas mileage, I haven't calculated what I'm getting as of yet, but suspect it's in the 10 mpg range. If you are concerned with fuel economy than I suggest that you get a vacuum secondary carb.

Good Luck!

 

wingnut, have you taken your car to the strip? If so what does it run.

 

I'd use some other cam besides that Bracket Master (a good cam in its day, it's been superseded) in a Vortec-headed 400 whether it's had routine bore maintenance done on it or not. The car will go faster with a XE268, or better yet, if the heads have had their valve guides cut like they should have been at the same time as they cut them for the larger springs, a XE274.

 

just remember man, I dunno if you have to pay for gas, but TPI will pay for itself if you do. if not then go with what you can afford at the moment to get the car running. a carb'd 406 is good for an average of 10 mpg, a TPI'd 406 can be tuned for 20-25 mpg average. I have to pay for gas myself, so FI is the only route I'll go.

 

Is there a way I could adapt a tpi system to an air-gap manifold?? Like drill and tap the nitrous bosses in the manifold and ad the fuel rails (customized if need be), and add all the engine sensors in a different location (because the tpi intake system would be gone)??? This might sound crazy but I think it would be kinda cool and also something different!!

 

What???

TPI chokes a 305. Who cares what it would do on a 400.

Some other fuel injection system without those long skinny runners might be a different matter. People do tha tall the time. In fact, Accel sells just such a thing; looks lot like a Vic Jr. with fuel injector bosses in it, and it comes with a 4-barrel downdraft throttle body. The engine sensors are pretty much all in the usual places.... coolant temp sensor in the water oulet, TPS on the throttle body, MAP sensor mounted wherever convenient, O2 sensor in the exhaust, knock sensor in the coolant drain hole, etc. No sensors have to be relocated. You can even get it with a port shot of nitrous pre-installed IIRC.

But it sure as hell doesn't have, or need for anything, those long runners. It isn't TPI.

 

Well, if you put tpi on it you could say by-by to all that 400+hp. You would still be fairly fast just because of the torque but not as fast as with something else. If you were made of money and wanted to go with something like a mini ram or something then you are throwing away power with the tpi setup. The tpi was origionally designed to go on the 305 to make more torque so it wouldnt be as noticable a drop in torque from it to a 350. It doesnt really flow above 4500 rpm. If modified they can go higher but without getting into real custom stuff you still have a max of around 4800-maybe 5000.

Ben

 

IMO 3.73;s are way to much for a 400, with as much tourqe as it should make 3.73's are going to run the engine out of its power band to quickly 3.23 or 3.42 would be a better choice, but thats just my opinion and you know what they say about that.

I agree with the cam thing, a 274xtreme or even a 284xtreme depending on how wild you want would be a better choice, look at the vortec headed 350's w/274xtreme cams. With being a 400 you are going to be able to throw more duration at it and get away with it. I could have went with a bigger cam in my setup but I do want it to be a street car.

I got confused on the induction part, are you talking about putting TPI on it? I think that would choke the engine down. Look at mike crews and 1BAD(crap I can't think of his name, smart guy though)about there TPI setups on 350's and 383's. You will need a lot of home porting to be able to feed the 400 with the air its going to need. I think a 400 w/vortec heads and a 274xtreme cam with an AIR gap and a 750 would be an extremely strretable and fast setup. Just my opinon though. Good luck. I hope to have mine running soon.

Jason

 

I wasn't referring to a tpi setup (sorry for the confusion). I was referring more to an Accel tpye setup but using a carb manifold, drilling and tapping the nitrous bosses to accept the tpi fuel injectors, and building a bracket to mount the tpi fuel rail. You would have to use the tpi sensors (used or aftermarket) and a burned prom and new chip for a tpi computer. It would end up looking like an Accel efi system but a LOT cheaper because you could use mostly used parts. Does that help clear it up a little? I got the idea from www.customefis.com

 

It really depends on your camshaft choice and intended use for the car. When racing, I shift at 6000 RPM. With the 3.73's, I'm still well below 6K at the end of the 1/4 mile (in 4th gear). If it's more of a daily driver, I agree, shorter gears would be better. My car ran great with the stock 3.08's, got better gas mileage, and had the potential for an insanely fast top speed. But bracket racing is what I built my car for.

Not yet, but I expect high 12's. I wanted to take it to the track this past Saturday, but I had to work. I hope to make it to the track this coming Saturday - I'll post my results here if I do. I'll be running on BFG Drag Radials, so alot will depend on how well I can get it to hook up.

 

Hey I plan on building a 406 also. The same article interested me in the 406 buildup! It is called the thumper mouse, But I am going to put a little more thump in ole thumper . I plan on going with a little larger cam and either a mini-ram or stealth-ram setup. I would not go with even a modified TPI setup. Reason for this is at higher rpm the TPI will not provide near what the others will(MR And SR). TPI has killer low end but you will still have killer low end, The 406 with the right combo is a torque monster :hail:

Note: low end 472 ftlbs at 2400rpm on the thumper mouse!

 

guys look at the cam and heads selected for that motor, I don't think its really going to be a revver or a heavy breather, ported TPI or a superram should do the trick for him, and make a fart load of torque for stoplight racing, his top end is gonna be crap with TPI but then again the motor is only peaking out at what 5200 rpm? that's not exactly a motor designed for top end running, if it was he should have a solid roller in there, with a .550"+ lift, dart or track 1 heads, with power peaking at 7000 rpm and then I'd suggest a miniram or sheet metal intake. if his 406 was doing that, it'd be an easy 600+ HP mill, but I think he wants a mild performance setup, ported or aftermarket TPI can work fine on it.

 

Yes, but even with a 350 a tpi wont hardly peak above 4800. With a 400 that demands more air he may really be struggling up top. I MIGHT consider it if the car is already tpi and strictly for street use, but if not I wouldnt consider it.

Ben

 

true, I'm just saying, that motor looks like TPI would be good for it. maybe a few HP up top sacrificed for a buttload of torque down low. No offense to anyone interested in that kinda build, but I think it's a wuss for a 406, cause a 406 is an easy 600 HP motor :lala:

 

That is a very streetable combo. You will also get more than 12 mpg (if you can keep your foot out of it) around town if you're playing nice, and decent mileage on the highway. I'm building up a 406 pretty soon here, but it will be more of a strip motor than street.

 

Here is My 400 setup and its streetable:
SBC 408

Engine: 400 SBC ID# 330817/14y139664/ T0508CSU
(4.125 bore X 3.750 stroke) after .040 bore (4.165 bore x 3.75 stroke =408)

Crank: Scat 9000 Crank 3.750 6.00, Internally Balance, Part# 400-3750-6000

Bearing: Clevite– MS1038P Mains and CB663P Rods

Piston: Wiseco Pistons, .040 over, 5.4cc; 430 grams, Part# PT020H4

Rods: Eagle ESP 4340 H-Rods 6.0, Part# CRS6000B3D

Block: Zero Deck: 0.000

Compression Ratio: Static-10:48 Dynamic-8:30

Cam: Grind: Crane 114681

Heads: AFR 195 Part# 1035 w/23º valve angle, 74cc, drilled steam holes

Head Gasket: Fel-Pro-1014 / 0.039

Intake: Edelbrock RPM #7101

Carb: Holley 750

Rear End Gear: 3:73

Transmission: Pro-Built Street/Strip 700R4

Stall Converter: A.C.T. 3000 Stall

Exhaust: Hooker Super Comp headers 1 5/8 Headers part # 2460-1 ceramic coated;
Hooker Super Competition high flow cat-back exhaust system, Intermediate pipe: 3 in.
* Tail pipe diameter: 2 1/2 in.
* Dual tail pipes out the rear under the bumper

 

DTL504,
What are the specs on your cam?

Ben

 

Here is my Spec Sheet:

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

I was thinking about using the Smaller CRN-113841 cam for the street, however as hot rodder we always think that bigger is better (114681)Cam ....

W/113841
2000 163.865784 430.147675
2500 205.845306 432.275146
3000 248.805634 435.409851
3500 304.736877 457.105316
4000 352.438354 462.575348
4500 391.840210 457.146912
5000 415.045227 435.797485
5500 414.930084 396.069641
6000 395.808228 346.332214

w/114681
2000 161.000305 422.625793
2500 204.819290 430.120514
3000 247.012802 432.272400
3500 305.812958 458.719421
4000 357.270813 468.917938
4500 403.406982 470.641479
5000 434.643005 456.375153
5500 450.014038 429.558868
6000 443.203003 387.802612

 

D,

Why did you stay with the smaller 190cc heads instead of going with a 200 or larger? If I am reading that cam sheet right thats a pretty good size cam, comp cams is hella easier to read. Sometimes I wish I would have went with a 200cc head but other more knowlegdable people said the 220cc heads would be better, i guess we will see. my cam is 288/294adv 236/242@.050 .540/.578 lift

 

Liljay
One reason for the 195cc heads was that they flow better at my operating range from idle -5500, where I wanted to make most of my power being a dedicated street engine. Now if I was using this car as a strip car I would have elected for the 220cc heads, which flows real good for a engine turning 6000-6500 RPMs. IMO, I think you plan on spinning your engine in the high rpms so if thats the case go with the 220 and the Big cam, which would call for a higher stall and gears to match. What I have tried to do and got plenty of opinions from people is to Max my low end performance. As always stated you have to build your engine where you spend most of your RPMs. It will not be beneficial for me to buildmy engine with your size cam and heads for a street performance car.
Hope this explain my reason for my combination......

 

I don't know if it's just me but, if you're operating range is from idle to 5500 then isn't that cam a little big? 244/252 duration? The camcard says the range is from 3400-6800, not exactly the range you're looking for. Granted the bigger cam will be less noticable in a bing inch motor, but still I think that's a little excessive if you're mainly looking for idle-5500. You should have gone with a cam a step or two down from what you have.

Correct me if I'm wrong, or if you have different plans for your motor, but for a street motor it seems a little much to me.

 

My engine should peak around 5800, and thats fine with me for a street motor with 2800 stall and 3.42 gears. I know that most think that I should be running 3.73's but with the amount of tourqe that I hope to have 3.42's should be enough. The cam I am running in my 400 would act completely different in a 350 and would peak around 6300 I think. Motown crate engines, like the 416 and 427 small blocks have insane cam's in them and peak from 5500-6000, I will have to try and find some specs on it so its not just hearsay. I agree 244/252 is big thats why I went with a step smaller cam to try and have some streetability. If I want to go cruise in a T/A I will get in my other one with a 305TBI(oh yeah, its a beast)This car is about one thing, going fast and I hope it does. Hopefully desktop dyno 2000 is within 8% like my engine builder said it is. I'd be happy then

 

I knew the displcament affected those figures, I just didn't know that much. How does it idle and how much vacumn are you pulling? I was planning on running a 235/235 dur cam in my 406 (AFR 190's, 11:1 CR) but I was thinking of going a bit larger.

 

I did get recommendation from Crane and other on the WWW.chevytalk.com board and they both recommended that I use the 114681, because I do plan on running it at the track a few times a year, I wanted the higher Rpm...

 

IMO, that is going to require more gear and a higher stall than my cam and I don't think the power band will be idle-5500. A 274 or 284xtreme cam would yeild a lower power band. Chevy high performance did a build up of a 406 and used a 284xtreme cam, can't remember what heads they used, darts I think, and made really good power below 6000. they used 200cc heads I think. I am trying to find the article online but haven't been able to yet

 

I would concur. The Vortecs have a rather weak exhaust side. A split pattern would be a better cam.