The more I read on this the more unsure I get. I'm building a 512 out of a 400 block and I'm currently in the bolt-on parts collecting phase. I need some opinions on what intake to run. Heads will most likely be worked over Edelbrocks or Trick Flows. This will be a 100% street driven motor and won't be spun past 6,000 RPM. Eventually it will get some kind of TBI setup as well.

I'm probably over thinking this and should just get an RPM Performer and be done with it. Ideas?

The camshaft, converter, rear gear ratio carb. size and intake manifold all need to match the intended application for the motor. That being said most single plane intakes are not very responsive at or below 2500 RPM and they will make more HP and torque above 4500 than a decent dual plane intake will on the same storker motor like yours
I have dyno tested several different intake combinations on 500 to 700 HP pump gas street motors and I like and use the Eddy Performer RPM on most of the normal guys motors. If they want the fastest and baddest sounding street cars then they get the M.W. heads and bigger and better single plane intakes that match the heads, cam and so on

Performer RPM is probably your best bet for street manners. A single plane with an annular booster carb would probably work also but might be more "touchy".

I agree with Andy and Cab. I use the Performer RPM dual plane on my 451 stroker (around 530 hp) going through the traps at 5.600 rpm at high elevens in a 4.000 lbs Charger with 4.10:1 gears and a 10" converter on regular (i.e. non-softcompound tires) Firestone Firehawks. Before that I used the TM7 on the same combo;it was decent but not as good as the Performer RPM.

Ragnar in Iceland

Open plenum especially if you go to tbi as the distribution is WAY better.........

I run a Street Dominator on my low deck 512. Love it!

The car has 4.10 gears right now, but I'm looking forward to dropping back down to a 3.55 after the motor is installed. The converter is a tight 10" Turbo Action. Haven't decided on a cam yet.

It sounds like a dual plane is what I want then. Thanks.

Check out the vid posted on here about frieburgh(sp)from Hot Rod mag where they tested carbs against efi and the problems they had w/a dual plane and efi distribution..........

We are essentially doing the same build. I think I will be going with a Torker that I will have Larry Smith at HP engines port and balance the flow. I need the hood clearance is why. I will be running throttle body injection probably FI Tech unit. I may get a RPM for mock up and check hood clearance. But pretty sure it is to tall in my case.

I went with the MI SP on my low deck Ed head 496. It tested well on the Hot Rod manifold comparison and I wanted best possible air distribution for EFI. A dual plane should help lower end torque... but with 512 CI you probably have more than enough already. I figured a little help at the top end was more important.

It is super responsive at any RPM. It did require some tuning of the electronic "pump shot" to avoid stumble on acceleration below 2000 RPM. It will now accelerate smoothly from 1200 RPM in overdrive if that is what I want.

I recently pulled it for freshen (pic). I'll post dyno results shortly. With >600 ft lb torque at 3000 RPM it does keep up with traffic OK...

Thumper,

How long ago was this video posted? I am having a hard time finding it.

Like a week or so ago on here.............Maybe someone can bring it up.......

Lets see, a 750 CFM carb compared to a 1000 CFM throttle body, thats a fair comparision, correct Me thinks a decntly tuned 950 CFM HP carb would have made more HP and torque than the 750 CFM did on that motor and intake

Slightly different in that mine is an RB so your mileage may vary...

I went with a Holley Street Dominator intake and Demon 850 Double pumper. The hood clearance is nice and clears with a drop base air filter. I did use a phenolic 1/2" spacer to help insulate the carb from heat.

I drive my car on the street A LOT and the street manners and torque are unbelievable! I had planned on upgrading to an FI-TECH fuel injection system but since it drives and performs the way it does, I doubt that will happen. Car starts instantly, doesn't load up at stoplights and is, in general, an absolute pleasure to drive!

Oh yeah, it's a 505" motor with Modern Cylinder Head ported Stealths and a hydraulic roller cam. Very smooth!

I need an overdrive for it to be perfect but 3.55's make it tolerable.

I would never have thought that would be an issue. So what I'm taking away from this then is I should use different manifolds and avoid a potential headache altogether.

This helped me out a lot. Seeing as how I still have the 5/16 fuel lines in the car I might as well upgrade them and inject the 360 this season first. I'll pick up an M1 single for the 512.

Thanks everyone.

Low Deck 512 with standard port heads?

Ported 383 Holley Street Dominator will IMO be best all the way around, OOTB a good toss-up between an RPM and the SD, but ported a SD will walk the dog and still fit under your hood.

But on a big cube motor AND....I had to run it out of the box I'd probably go with an old TM6 (tarantula) or the Weiand X-cellerator over the RPM, but a ported SD would still be my first choice. The M1 is about as good out of the box as the SD, but it's tall/skinny plenum runners are tougher to port, the SD is easier to work the runners and you can get better taper for good power...but opinions vary.

I'd highly recommend you send it to Larry Smith at HP Engines; I used to port the mess out of SD's and get them to flow from ~270 to ~310-315, that's plenty for 600+ hp. As a general rule if your intake port doesn't outflow your head by ~5-7%, you're leaving power on the table. Here is some of Larry's handiwork (mine could never be this pretty, lol) on a Mopar 337 on my 517 Max Wedge Low deck.

Wow, that's nice.

Where is Larry/HP Performance and what does he charge?

PM me if you like..

Hollis Page is a Moparts sponsor here, he's in central North Carolina and Larry works at his shop. Both of them are about the nicest people you'll ever meet and are AWESOME engine builders....and they LOVE MoPars!

Larry can give you a quote, I know it varies by the intake. I know when I used to do Street Dommy's it would take me about 3 hours of solid porting and roof radius work, and maybe another hour of finishing (Purdy up) work. I think I heard someone say Larry is doing a Torker for him.

Thanks! I have not paid that much attention to EFI retrofits, but I don't recall hearing of a problem with TBI on a dual-plane. The video doesn't really describe what they did to understand the problem. Clearly a carb has an advantage over TBI of using staggered jetting to compensate for manifold weirdness, but the video states the carb was square jetted. It's a shame they were not able to get to the bottom of this during the dyno time. Would another vendor's TBI had the same issue? I bet there is more to this....