[Skip Fix]

Figure the NHRA stocker folks are running deep in the 11s with those unported!

[Pav8427]

I would be curious to know if removing that much material had any effect whether the intake stayed straight and didnt warp.
Wouldnt think so. But a straight edge should tell us.

[Formulajones]

Originally Posted by Jay S

Shaker455 do you have any thoughts on the effect of the gap under the primaries on the carb signal? It seems backwards to me too have the divider drop on the primaries instead of the secondaries? I am running the drop on the primaries like the pictures show. But I wonder if I shouldn’t put the EGR plate under the carb back in, cover the EGR holes in the plate and cut down the divider on the secondaries?

I recall Rocky flowing the PB4. It did really well.

Jim Hand found decades ago that having that divider flush with the primaries of the carb was very beneficial to part throttle drivability (better carb signal), and then just cutting down the back portion of the divider. Not only just having the front of the divider flush with the primary of the carb, but also keeping the diameter of the primaries on the intake the same as the carb base. This turned out to be the best combo that Jim ran for many years.

That is generally how I modify all these intakes and it works exceptionally well, and easily supports over 500hp with either the iron or aluminum version.

[Formulajones]

Originally Posted by Skip Fix

Figure the NHRA stocker folks are running deep in the 11s with those unported!

So are the pure stock and factory stock guys at the muscle car drags.

Ported they are into the 9's.

[GoreMaker]

Originally Posted by Pav8427

I would be curious to know if removing that much material had any effect whether the intake stayed straight and didnt warp.
Wouldnt think so. But a straight edge should tell us.

I was worried about that, especially with the acetylene torch cutting. But I placed the intake manifold on the heads and everything is perfectly flat and straight. That casting is SOLID, there's a good reason it weighs 45+ pounds as-cast.

Even if it wasn't perfectly straight, having the center section of the mounting flange removed allows greater flexibility to accommodate any twist in the runners as the bolts are tightened down, and any wave would be taken up by the gaskets. This isn't a boosted application, so sealing isn't difficult.

The carb flange is also still perfectly flat, but the carb gasket would take up any unevenness even if it wasn't.

[GoreMaker]

Just to be clear, despite all the material I've removed, this is no lightweight intake manifold. The Crosswind aluminum manifold weighs about 10 pounds as-cast, and that's with the water crossover attached. The Edelbrock Performer weighs 15 pounds as-cast. The HO reproduction weighs 8 pounds as-cast. My endless hours of grinding on this cast iron manifold resulted in a 27 pound part, without a water crossover. It's still VERY hefty and VERY stout, even if it's significantly lighter than it used to be. I'm guessing porting will remove another pound or so.

[shaker455]

Originally Posted by Jay S

Shaker455 do you have any thoughts on the effect of the gap under the primaries on the carb signal? It seems backwards to me too have the divider drop on the primaries instead of the secondaries? I am running the drop on the primaries like the pictures show. But I wonder if I shouldn’t put the EGR plate under the carb back in, cover the EGR holes in the plate and cut down the divider on the secondaries?

I recall Rocky flowing the PB4. It did really well.

Jay, after many Performer & Performer RPM divider mods allowing snap install for any configuration & ease of testing, I found fully divided on primary's shows best signal.

I still have my RPM I machined a snap in T-bone for the rear divider

[shaker455]

Originally Posted by GoreMaker

Just to be clear, despite all the material I've removed, this is no lightweight intake manifold. The Crosswind aluminum manifold weighs about 10 pounds as-cast, and that's with the water crossover attached. The Edelbrock Performer weighs 15 pounds as-cast. The HO reproduction weighs 8 pounds as-cast. My endless hours of grinding on this cast iron manifold resulted in a 27 pound part, without a water crossover. It's still VERY hefty and VERY stout, even if it's significantly lighter than it used to be. I'm guessing porting will remove another pound or so.

Here's the Fat runner P4B QJ i.put on my 67 GP

[GoreMaker]

Yeah that looks completely different from the current Performer. Why isn't that still in production? What's the reasoning behind stickimg with the defective design? I don't get it...

Having said that, it looks like it's missing some threaded holes that my stock manifold was using. I won't know for sure until I have everything assembled again

[GoreMaker]

Since this seems to be more interesting to people than I expected it to be, here's a few more detail pictures along with a comparison to the RAIV/HO reproduction manifold, which is the closest cousin I have on hand.

Here's the underneath, side-by-side. Really illustrates the difference in the EGR area.


The EGR hole is blatantly obvious here. I'll plug it after the manifold is ported, either with aluminum or JB Weld. Can also see where those fins used to be. I'm still planning a final finishing of the surface to get it more smooth once the paint's been stripped off.


Compared to the older design.


Front comparison.


Rear comparison.

[shaker455]

Originally Posted by GoreMaker

Yeah that looks completely different from the current Performer. Why isn't that still in production? What's the reasoning behind stickimg with the defective design? I don't get it...

Having said that, it looks like it's missing some threaded holes that my stock manifold was using. I won't know for sure until I have everything assembled again

P4B QJ was designed before the energy crisis in mid 70's with generous runner volume, the Performer we know today is the end result of the crisis.

This intake made the car much smoother over the factory 4-bbl Carter carb intake

[GoreMaker]

Got it media blasted. Now the little nick where my chop saw went in a little too far is especially noticeable Time to get it sent out for porting!

[Jim Moshier]

Is Dave at SD Performance taking on new work? I thought he was still playing catch up on what he had? His website still says no new work!

WE ARE WORKING IN THE SHOP AS MUCH AS POSSIBLE WITH A FOCUS ON CATCHING UP ON EXISTING JOBS. WE ARE NOT TAKING ON ANY NEW WORK UNTIL FURTHER NOTICE AS OUR PRIORITY IS TO CATCH UP AND GET OUR CYLINDER HEAD BUILD SCHEDULE BACK ON TRACK AS WELL AS DEAL WITH REPAIRS AND CLEANUP ON OUR PROPERTY AFTER BEING HIT BY A LANDSLIDE LAST FALL. THANKS FOR YOUR PATIENCE AND UNDERSTANDING, WE HOPE TO BE TAKING NEW ORDERS LATER THIS FALL.

[Cliff R]

Just a note on dual plane intakes and dividers. It is best to leave the divider intact and full height. At most you can remove a small portion of it between the secondaries, but that is more easily accomplished by just using an open gasket under the carb. The Olds Q-jet gasket is solid across the front and open between the secondaries. They are apprx .160" thick so two stacked together works well. You can also use a 1/4" thick four hole gasket and snip it out between the secondaries.

I've lost count of how many dividers I've had to make and install where someone following good on-line advice ground most of or all of it down. The symptoms from doing this can be minro to severe. Usually you will get a HUGE stumble/hesitation/bog going quickly to full throttle with good traction. Once past "transition" they work OK and may even show a few more HP way up at the shift point.

The dyno and drag stip tells us from the testing I've done that spending a bunch of time with the divider does next to nothing but leaving it in place improves throttle "feel" in the "normal" driving range.

Same thing with spacers, fully open was HORRIBLE for all testing, dyno, street and at the track. Fully divided was OK, four hole not that great, and semi-open (similiar to what Jim Hand used on his 455) the overal winner everyplace.......FWIW......

[android 211]

Theres a few PB4s. Some have narrow runners like a Performer and some, I think the older ones, have fat tapered runners. Some are square flanged and some are for Spreadbore carbs. The thicker runners ones are preferable for hi-perf use. I recall the dyno of the EGR intake showed little difference compared to the non EGR intake. The D shape to the secondaries is to reduce/inhibit reversion into the carb. I can't comment on the lip around the primaries. Must help exhaust distribution of the EGR function. If you are using 6X heads in a build and want to use the cast iron intake, look for the 72 version. It fits the later heads exhaust crossover correctly but has no EGR. The choke design is different but as long as you have the right rod it works the same. I already did it.

[NeighborsComplaint]

Could have just used an intake gasket with a crossover block-off insert and got the same result with a lot less work.

[78w72]

Originally Posted by NeighborsComplaint

Could have just used an intake gasket with a crossover block-off insert and got the same result with a lot less work.

saved 15+ lbs & looks way cooler

[rohrt]

Originally Posted by shaker455

Jay, after many Performer & Performer RPM divider mods allowing snap install for any configuration & ease of testing, I found fully divided on primary's shows best signal.

I still have my RPM I machined a snap in T-bone for the rear divider

That machined divider is really cool!

[NeighborsComplaint]

Originally Posted by 78w72

saved 15+ lbs & looks way cooler

Every kid needs a hobby I guess but now he has to cobble together block off plates or run a separate exhaust crossover.

[78w72]

Originally Posted by NeighborsComplaint

Every kid needs a hobby I guess but now he has to cobble together block off plates or run a separate exhaust crossover.

instead of being negative, it would be better to actually read his comments & see that hes using KRE Dports that dont have an exhaust crossover...