Im beginning to wonder with my lack of low end power if my manifold isnt a dual plane. It just screams when it revs, but low end leaves a little to be desired. I have a holley street dominator that is discontinued, and it has a divided plenum with EGR. The manifold doesnt appear stepped like most of the other dual planes Ive seen. Did they ever make an emmisions legal single plane? Thanks .

 

I don't know. I can tell you that there is such a thing as a single plane intake manifold with a divided plenum though. Not sure what you've got, but it does exist.

 

the Holley street Dominator is a just an average dual plane if I remember right.
The don't really make a single plane with a divided plenum, sorta does against the definition of a single plane. Some manufacturers do offer a slide in divider plate or spacer you can use..but that doesn't really count. I don't get the theory of that either...if you want a dual plane buy a real one. I've never seen an emissions legal single plane either.

I'd look more into a tuning issue for your problem first.

 

I think im going to get a fresh coil and some wires first, and dump my POS paper filter. Motor is still in test and tune stage as it is now. We're going to check the timing and such soon, and theres a noisy lifter to fix. All I know is it really moves when you rev it. Got it to 5200 in first today, nailed second and the damn thing kept pulling and I got scared and backed off. I love it! Oh and if it matters, i still have my stock quadrajet.

 

Holley did make a single plane intake with a divider
and egr. It also had a passage joining the back two
cylinders. (7 and 8). I think the model # was 300-28Z.

Was never that great of an intake. Too much compromise
in the design. They made the runners small to increase low
rpm velosity (torque) at the expense of top end breathing.
A modern hi- rise dual plane like the Performer RPM
will make more horsepower with better torque and throttle response.

 

When I said it existed, I was thinking of the Weiand X-celerator, the intake with the removable divider, and a Holley manifold. It had a capital letter in the name as well if I remember right.

 

PN 7546 I have one sitting right in front of me.

 

300-28z? Yep thats mine. I paid $75 for it used, thinking I was saving money over a new one.
Well, Looks like I have to go out and get another one. That puts off the torque converter for a while. The motor almost feels like it has turbo lag, not really coming alive till 3000 rpm. Maybe I can get $50 or so for the manifold. I appreciate the help guys, and now I'm just pi$$ed because I'm out $75 and its gonna take another month to get the cash for a new one.

 

Most dual planes run around $100. What do you guys think about the stealth? It is a dual plane good from idle to 6500 ( if I remember correctly) from weiand. I almost bought that one, but I got the X-celerator myself.

 

I'm a fan of the Stealth. Definatly my favorite dual plane.

 

I have the stealth intake. It's about perfect for a street/strip or fast street car. Lots of low end grunt, and it can breath at higher rpms.

 

Can you get a Stealth manifold that is emmisions legal? I kinda need to pass emmisions up here. Of course I shouldve thought of that before the 350.