Disclaimer: This isn't an F-body

Assumptions: Assume that the divider *could* actually be seal welded in the intake and then machined flat up top.

Here we go, I'm have been recently inspired to get rid of my GM dual plane aluminum intake for vortec heads. This is the intake that comes on the 330hp crate engine.

I have my new carb in the works, but I'm trying to decide on a new intake.

Carcraft recently dyno tested the 350HO crate engine and got 371 HP out of it. This is 51 more horsepower than GM advertises. Which leads me to believe it very well be a more powerful motor (or just as powerful) as the ZZ4. Only, gm can't sell a cheaper motor that makes more power. The zz4 is the bread & butter of their "crate engine" division.

Carcraft used an Edelbrock RPM and a 750 for the test. So, I got a 750 (3310-1), but am investigating which intake to use.

Vizzard says if you have relatively high compression and short duration that a single plane can work quite well on the street. If I understand right it won't make 'as much' torque as a dual plane, but will make more torque below the peak and, of course, make more power.

So, I'm not totally against trying out a single plane, but everyone says that their experiences have shown the RPM to work better in a heavy street vehicle.

This leads me to my questions. First off, the motor is in a 1988 C1500 regular cab pickup. It's got a th400/2400B&M/3.42 combo behind the motor. Exhaust is open Hooker competitions when "competing".

All marketing aside, does anyone have any dyno testing of the air-gap VS. the performer RPM?

I'm looking for more horsepower and more torque from the swap. Hoping to get this by installing an intake with a better design.

I know in TPI cars they (GM) used long runners and that 'long runners' promote torque. I'd assume this builds more velocity and cylinders fill better until flow rate is increased too much.

So, what am I looking for for a 4000+ lb truck?

If you could comment on intake runner volume and length AND plenum volume while saying how each affects total power out put I'd appreciate it.

I'm also not against modifying an intake at all. Like if removing the upper portion of the plenum divider in an RPM would offer greater benefits or not. Another example, purchasing a vortec victor intake and putting a plenum divider in it. Or increasing the volume on the intake runners on my GM intake and adding more volume to the plenum.

I don't have time to read Bret's favorite book on intake system design, but if I could get some cliff notes from it... I'd really appreciate it.

Ben T.

212/222 on 112
9.1:1 compression
2000 to (5500-6000-ish) operating range

 

Don't try to reinvent the wheel (or the SBC for that matter).

Use the Air Gap or the RPM, and IMO, a vacuum secondary 750. Don't bother trying to re-engineer a Victor or other manifold. You aren't Vizard...yet.

I would not call the CR on the HO engine "relatively high".

Remember stock Vortec heads are better than most old iron SBC heads with significant porting. DV can get more flow out of old heads with extensive porting, true, but much of his testing was done before Vortecs. He likes them a lot.

Look at the torque of the HO from your converter stall rpm on up. Both the dual plane and vacuum carb will probably help there.

Short victors (like Jr.) don't have runners all that long. Super Vic does, but that's for engines with another 100++ hp, IMO.

Good luck!

 

"You aren't Vizard... yet."

A polite way to put that... Hope to know a lot one day though.

I agree with not calling 9:1 "high". If the heads come off to have the seat springs cut and push rod holes elongated then this is not a matter... after the fact.

Still looking for someone with experience from the RPM and the Air-Gap RPM.

So don't reinvent the wheel, huh. I heard these RPM intakes were pretty good. I'll keep this in (zelous) mind.

Ben T.

 

i've done back-to-back dyno tests ,same engine, same day

the Edelbrock RPM-Air Gap is a great intake

the tests were RPM Air-Gap -vs- Edelbrock Victor Jr

the Air-Gap was better till 5000 rpm

at 5000 rpm they were even

above 5000 rpm the Victor Jr pulled away

the most amount of average Torque and HP was with RPM Air-Gap

i posted this info 1 year or so at PreStage.com

in that post was all dyno data, rpm, TQ, HP, Ve%, BSFC,BSAC

 

i beleive Vizard was referring to the low profile type single plane intakes such as the wieand street ram WITH his divider extenders welded into the runners. he said this worked very well on the street on 9.5:1 motors with less then 280* seat to seat duration. I dont belive he was reffering to the Victor JR. or the weiand Team G. these manifolds have relativally larger runners(volume). when you use an open plane manifold on the street you'll see better results with carbs that have annular boosters. the 3310 does not have them and there fore they aren't as responsive to low engine vacuum, which can cause poor drivablity and loss of low end torque which the open planes are notorious for(because of their design, high RPM).

 

Hey maxracesoftware, have you ever done any back to back testing between the wieand Stealth and the RPM(non air gap)? i was just wondering. i had a stealth and an 8004 with a 1" spacer. i thought the 8004 with the spacer pulled harder than the stealth did. just curious. I've never seen any independent testing between these two.

 

between the wieand Stealth and the RPM(non air gap)?
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not between those 2


the 1 inch spacer makes a gain sometimes and sometimes it doesn't , just have to experiment on the dual-plane