carb question

[88Vic]

You mean that you want to run side pipes, as in you can see the pipes running under the side of the car? Or do you want it to be under the car but having it exit in front of the rear tires? And to answer your question yes, a few guys do have exhausts like that, but I don't think anyone here has side pipes or lakes pipes.

[Nathan in MI]

hmm ok.. so the edelbrock intake/carb combo i was looking at would be more than what i would need... i was looking at this combo:

http://www.edelbrock.com/automotive_new/mc/power_package/manifold_carb_kits.shtml

part: #20344

its an 800cfm carb

also has anyone done a cobra-like exhaust?.. meaning.. running the exhaust from the headers down the side of the car under the doors and out right before the rear tires?

800 is an awful lot of carb for the average 351. 625-650 is closer to what you want unless that engine is gonna be seriously built.

[DuceAnAHalf]

Definitely go single 4-bbl.

Dual quads are really needed on anything these days except for pro-stock and top fuel cars running 6's and under in the 1/4 mile. Dual quads look awesome, but they are expensive to buy and maintain.

pro-stock still runs carbs, it is not uncommon to see a pair of split dominator carbs. A split dominator is where they take a dominator and cut it into two 2 barrel carbs, this allows for better placement on the manifold t for better fuel distribution.

Top fuel does not use carbs, neither does funny car, they run mechanical fuel injection, 10 injectors are placed in the throttle horn above the supercharger, 16 in the intake manifold and two per cylinder in the cylinder head.

[Fordman75]

Just go with a Weiand Stealth intake with an Edelbrock 600(performer carb ) or 650 (Thunder series carb ). You'll get good power and still be streetable.

The Edelbrock carbs are simpler to tune. If you don't want an Edelbrock carb then a BG Road Demon 625cfm would be my next choice.

[AOD]

I have a Weiand Stealth intake and Edelbrock 600 carb. Don't forget you'll need the Lokar throttle cable, throttle bracket and kickdown cable for the trans.

Expect minor fitment issues if you have an HEI distributor going into the motor. Most guys still use the Ford ignition so they don't have this problem.

~Adam

[Grand Marquis GT]

you in rochester, NY by chance?

[1987cp]

Interesting, that BG Road Demon seems to be priced similarly to the Holley you were looking at on summitracing.com. I wonder how they compare?

I do believe a 750cfm single four-barrel is the most you'll need unless you're making at least 500 horsepower, give or take, and shouldn't even be necessary unless your combination is pretty radical - that is to say, very strong heads such as the Edelbrock Performers or better, maybe pushing the limits of a Performer RPM intake, and of course running a fairly wide-duration cam that forces your engine to operate at very high RPMs. "Better", in this context, is referring to what makes big power numbers up top, but isn't necessarily any good for daily driving. For example, a Victor Jr. intake for a 351 is advertised to make power from 3500-7500 rpm. That means that a combination optimised for that intake (which is to say, one that would experience a restriction with a Torker II or smaller intake) would probably require a torque converter stall rating of at least 3500rpm (expensive!) - and only at very high RPM would it really begin to experience a restriction from a 750cfm carb.

I've got a copy of Desktop Dyno that I got from Tiggie, who in turn got it from Nate, and I've put together flow profiles for a bunch of readily available cams and heads (and more clearly labeled others that were in there already), and while these simulations are far from perfect (not enough input data to be truly realistic), they indicated only minimal restriction (generally speaking) with even a 600cfm carb on under-400hp applications. I also learned a bunch about a few cams I hadn't known about, such as a certain Crane flat-tappet (read: cheaper but somewhat shorter-lived and less desirable than a hydraulic roller) that delivers big power numbers up top (i.e. around 5000rpm) but maintains a very streetable torque curve down low and looks to me like it ought to work with a relatively cheap 2000-stall torque converter, which can be had for about $160 if you're running an AOD transmission.

Since it's now possible to get four-barrel carbs as large as 1200cfm or more, I wouldn't think multiple carbs would have a lot of practicality unless you need the huge airflow up top but want to set it up so you're driving on only two barrels most of the time, such as a Six-Pack setup where the center 2V opens up first and the fore and aft 2V carbs open up later, delivering effectively two primary and four secondary venturi.

I guess you could say that my way of thinking thus far is not to go bigger unless a noteworthy restriction is expected, especially on an engine intended for street duty in a heavy car. More to the point, the regular Performer 351 intake manifold is advertised to make good power from idle-5500rpm and said to support at least 300hp; the Performer RPM and Performer RPM Air Gap are rated from 1500-6500rpm and have been used on engines up to nearly 450hp such as the 351Ws built for the Starsky and Hutch movie cars. Better yet, a combination optimised for this sort of RPM range still work well with a relatively cheap torque converter. Needing more RPM than that on a street motor is pretty unlikely, and running something more radical such as a Torker II, Victor Jr., or Super Victor (in that order) will in most cases yield less than optimal results.

[phayzer5]

Damn, i guess my 2400 stall converter isnt going to be enough for the 408, 4000 stall here I come...

[1987cp]

Your 408 won't be making power until 4000 RPM?

[SLYDAWG]

Convertor

Damn, i guess my 2400 stall converter isnt going to be enough for the 408, 4000 stall here I come...

Pick the convertor based on the power band of your cam.
A 4K tc will not be streetable.
The 2400 should be real close.
I have a 2500 to 2800 that I am saving for the 408 when I build it.

[SLYDAWG]

Carb

"800 is an awful lot of carb for the average 351. 625-650 is closer to what you want unless that engine is gonna be seriously built.
Just go with a Weiand Stealth intake with an Edelbrock 600(performer carb ) or 650 (Thunder series carb ). You'll get good power and still be streetable."

I must agree with above posts.
The Stealth is a good intake. Choose a carb in the 650cfm range for streetability.
The Holley Avenger series is new and improved over the older style, and the 670 is good up to ~400hp.
Worth looking into.

[phayzer5]

I guess my jovial tone doesnt come across so well when my comment is typed

The 2400 will be fine. When I take the converter out to be rebuilt for nitrous use, i might up it to a 26-2800 unit. I would like to keep some street manners in the car ,)

[1987cp]

Ah, gotcha. I thought maybe you were joking, or maybe you really were planning some insane 8,000-rpm combination that wouldn't pull for squat at street RPMs!

Wasn't there a thread where you wrote up what's going into that motor?

[phayzer5]

I've posted bits and pieces over the past year of whats going in it. It would be a pretty good idea though to put it all in one thread

[1987cp]

I've posted bits and pieces over the past year of whats going in it. It would be a pretty good idea though to put it all in one thread

Great! And we'll all keep our eyes open for it and then swoop in and lambaste everything you did.

(just kidding, I'm assuming it'll actually be pretty nice)