Reviving the debate - Single vs. Dual...

[ViperMan]

Hey all,

So I reserved a spot on the can this weekend with some new magazines that arrived while I was in Ohio.

I had a Mopar Muscle magazine (just subscribed!) and on the cover was a teaser for a 596hp, 505ci engine build-up.  In the table of contents, it said, "You can win this engine!"

Turns OUT, it was the engine given away at Carlisle!  So no, I can't win it. 

BUT, to get to the point, they did a 505" with a refurbished block (what I'm doing.)
They used a Comp Cams cam with hydraulic flat-tappet lifters (actually less than what I'm doing)
They used Edelbrock RPM heads with porting (what I'm doing.)
They used a high volume oil pump (what I'm doing,)
and a 950 CFM carburetor (what I'm doing.)
Lastly, they used an Eddie RPM dual plane intake, which I'm NOT using...

I was going to use a Holley Dominator single plane intake because that was recommended by members here for use with Nitrous.

They did NOT use any nitrous (reasonably so,) which is still on my horizon...  Then again, if my engine turns 550 or more on the dyno, I won't use nitrous because the Keisler auto trannies are only good up to 650 lb-ft of torque anyways...

So I revive the debate:  Single Plane or Dual Plane and WHY?!?!

Jeff

[MEK-Dangerfield]

Use the Holley SD.

I don't know what kind of gears you intend to put in the rear, but I'm guessing you will want to spend some time at higher RPM's with a built up engine like that.


  Mike

[71chally416]

You'll have all kinds of distribution problems running a dual plane intake with Nitrous. They're good for mostly stock or mildly modified car engines and little else. Once you use ported heads you need the volume of a good single plane, and make sure it's matched to the head ports. You have to remember that at 6,000rpm the cylinders will get little more than what's contained in the head port and manifold runner connected to each one. If that's inadequate the motor will just nose over and stop pulling. I've seen motors lose 40-50hp between 5,500 and 6,000 on the dyno because of inadequate port and manifold volume. It will act like a rev limiter. 

Some people mistakenly think over-reving the motor in 1st gear and then feeling that big kick when you finally shift it is power, but it's just that it makes way more HP at the lower RPM. 

[bb71challenger]

I had the same question but it was answered by a few people whose engine building skill makes me a believer. Its gonna be a Holley Street Dominator on my 440/stroker

[71chally416]

Most of the guys I know around here run the Victor on the big blocks. That was also my choice with the 416 SB. 





 

[Chryco Psycho]

A customer has a 510" stroker with the 950 , big solid cam with 580 lift & the SD single plane intake , , it is hard to let the clutch up Without spinning the tires even at idle , do you want more bottom end response ?? There is Nothing the SD cannot do that a dual plane is going to make better
 the Victor works too but are you better off with more intake flow & a 2" air cleaner or slightly less intake flow & a 4" air cleaner I have seen over 40 hp lost due to a small air cleaner , yes even a K&N or similar type

[71chally416]

The smaller the runners and the Intake plenum the more it will rock the TQ curve to the bottom, the harder it will make a car to hook up and the more the motor will gasp for air in high gear. That's why I prefer to port the crap out of my heads and get the most volume I can in the manifold plenum and runners. That eliminates dual planes and street manifolds from my shopping list. Nothing sucks worse than losing a race in high gear when you run out of motor. Besides, they don't have the meat necessary for port matching to good ported aluminum heads. Using the extreme type lid on an air cleaner so it draws from the top is just as good as a taller element and it fits under a stock hood with a Vic and a spacer better. 

 

[nivvy]

The only dual plane i would ever run is the indy 440-2d ...... 

[71chally416]

That's supposed to be a good Intake, but again I would avoid it if using Nitrous. 

[ViperMan]

It sounds like Nitrous isn't even as much the concern - it sounds like for a strongly built engine, which is what I'm aiming for - the single plane is still the way to go.  I honestly don't know that I'll run nitrous due to the limits of the transmission.  We'll just have to wait and see - I can always add a plate system later.

Just to make sure we're clear, this is the Holley Street Dominator intake, part number 300-14... ...right?  Oddly enough it's available through Amazon.com at the lowest price I've found yet.

Thanks for the insight, guys.

Jeff