408 Magnum

Planning on stroking a 5.9 to a 408. Will it have enough air flow with the stock EFI throttle body and intake? Was going to use Eddy heads.
Thanks

That question is awe fully General. Would you care to add some specs like compression ratio and cam specs along with its intended useage?

The stock throttle body on the engine flows 670cfm *I think*
The heads barely flow better than 200 CFM. This is fine for stock and mild camshaft upgrades.
The stock computer needs to be flashed by someone who has all of your exact specs.

Going in my Dart with a manual tranny for street use. 355 gears
Shooting for 10-10.5 CR.
Edelbrock says their heads flow 251 at 500" lift. Probably will go with 500-540" lift cam.
I'm just in the planning stages.

The intake will flow plenty of air for you...

Remember that these intakes were designed for torque because of their long runners, not HP

Dan

I would consider running the Hughes/edelbrock intake on such a motor.A ported/modified kegger will work but it is leaving a lot of power/rpm on the table.

Was hoping for around 450HP. I want to drive this car all over, Vegas, CA and maybe Carlisle. I want EFI without spending 2000.00 for it and is why I'm looking at the factory setup. One reason I want EFI is that we have more change in altitude just in my county than most states do, 4300'-10800'.
Does anyone make a larger throttle body?

there are several.
if you go to the dakota forums there are a couple of people that mod the stock one pretty cheaply. going from I think the 48mm they are to 50 or 51.
haven't look here in a while, but he used to list them
http://www.dakota-durango.com/forum/forumdisplay.php?f=4

there is a company that makes some, and they make even larger than that.
http://www.fbthrottlebodies.com/
58 listed on the front page.

Awesome! Thanks

Go to http://www.hughesengines.com/Index/produ...G9kZ2UgTWFnbnVt and look through what Hughes Engines has for the magnum motors.They have throttle bodies as well.I am going to be using some of their stuff on my 5.2 Jeep.

I don't think you will get 450hp from that kegger intake. They are only good to 4-4500 rpm, maybe lower than that with a stroker. Mopar performance and Hughes engines have what you need.

use an M1 intake and 48 lb/hr injectors, especially if you are using a stickshift

I'd say get on the phone to Hughes. The MP Magnum FI intake seems to be hard to find and at a list price nearly $600 it's a little expensive. Looks like Hughes can get you farther along the road for the same amount. But maybe just maybe they can squeeze 450hp out of that beer barrel intake, I don't see how but I am not running a dyno either.

R.

Especially in a Dart w/a manual and a 408 you don't need monster low end torque, which is what you'd have with a kegger. Hughes sells a special Edelbrock RPM set up for a Magnum (injector bungs, stands for the fuel rails, etc), but if you're handy you could modify a normal RPM and save some $$$. I also doubt a kegger could get you to 450 HP (not as easy as an RPM anyway)

Well, reading some comments by people who have approximated the Hughes mods to the keg, which involve shortening up the runner length inside the keg, low end torque is reduced by the mods.

If one had a decent budget the Hughes/Edelbrock injection manifold looks really nice and has the advantage that one could run a four-barrel on it in a pinch. But maybe they have a better idea which is why I suggest direct contact, rather than speculation which is what I'm doing here.....

One thing for sure, camshaft selection is critical with factory EFI, even if it's been modified some. And that's another Hughes specialty.

Another way to go would be a stock keg with a light pressure turbo, just 4-5 psi to help the air through the runners.

One last thing, there have been plenty of guys hotrodding the Mag motors in pickups and there is a lot of info out there on the Web about what works and what doesn't.

R.

The Hughes air gap is real nice above about 3000 RPM, it kills a lot of TQ down low VS beer barrel, I know from personal experience. The one thing you can not aproximate with the beer barrel is the air gap. The plate on the bottom of the beer barrel heats up the air in the plenum really bad. Maybe one could glue a sheet of phenolic resin on the bottom of the plate to insulate it, I have also added a sheet metal layer over the lifters and such to keep the hot oil from splashing all over the bottom plate. I suspect the kegger could make significantly more power if you could keep that heat away from it. When it was 7* below zero F the other day my IAT never dropped below about 97* once the engine was warmed up good and that was cruising at 75mph, around town it was showing about 110* most of the time. I put a hughes air gap on one one time and moved the IAT into the runner like factory and it was waaaay cooler but still lost power down low.

If your doing a budget EFI you can run the kegger for now then when your wallet recovers you can grab the hughes. Your Dart will probably not miss the TQ like a Ram 2500 with a 5.9.

Mark, I've built a few of those magnum motors by now

in my Dakota, I have a stock short block, cam, headers, Edelbrock heads, M1 4bbl intake with 2bbl adapter, and an F&B 58mm TB

the whole thing bolts into my truck like a stock production motor.

You can get what you want easily. Stock computer, wire harness for EFI, use SCT to tune the computer to your CID and cam specs. there are 2 top SCT tune writers I would suggest to you.

but, to answer JUST the question you asked, Yes, there are larger aftermarket 2bbl TBs that bolt on like stock, and use stock sensors. F&B is probably the best you'll find. they offer different sizes too. for a 450hp 408, I would suggest either their 55mm or 58mm TB.