Sp2p vs performer intake for small block?

I have a 1968 d200 with a 1970 318. It currently has the sp2p on it.

20 years ago, when it was put on, it was discovered that it had a crack that caused an oil leak (what I was told from the previous owner) and was fixed via epoxy. I have not seen nor investigated past that statement. He is a good friend of mine, so I’ll take his word.

The motor has 30k miles on a rebuild, but it is a grease ball. It was driven the 30k miles, then parked because the owner (my friends nephew) passed away from cancer. Maybe 5 years on that rebuild...

So I assume that the intake has been leaking the whole time it was driven.

I have a performer intake that I “could” borrow from a spare motor.

Between the 2 intakes, which one is more favorable? I’m not going all out power, just a nice cruiser, and Home Depot duty. I would like more fuel mileage if anything. I’ll be running a 600 cfm carb on either intake.

So... fix sp2p or swap performer?

The SP2P is a real turd. The ports are smaller than a stock 2 barrel intake. You could drop a peanut down the carburetor and block 60% of the airflow in whichever port it went down.
The Performer 318/360 has ports similar to a stock iron 4 barrel intake. The main advantage it has is the reduced weight. It is a better choice than the SP2P by a mile though.

The SP2P is strictly for mileage. As franky said, the ports are REALLY small. Pinch off your nose, cover your mouth, and RUN. That's basically what an SP2P does to your engine.

The old performer I had looked like my 1972 340 intake.

The performer has 318 sized ports and is ideal for that engine. If you had a 340 or 360 you would probably want to gasket match and blend a bit but it will bolt on and work fine as-is. The performer is also one of the few aftermarket intakes that will allow you to bolt up a factory AC compressor in the stock location.

That is 100 percent why I used one on my old 340. A/C and easy to port is was almost like the 340 one night wise etc.
Was a better to choosecthag than others.

Other than a few extra pounds, the factory 340 intake is within 15 hp or so of the performer, basically apples to apples. If you have the cast iron don't be afraid to run it.

Boom!!!! There it is.
Truer words have never been said.

I’d run a stock 2bbl intake and carb before I put on one of those.

And their “greatness” isn’t limited to SB mopars either.
They suck on everything.

Friend of mine has a 68 Camaro ss 396.
One of the local 396 gurus gave him a recipe for a 400hp hot street build.

9.5cr, comp 280h magnum cam, Ede 750 carb..... sp2p...... no headers.

He wasn’t to impressed with it, and after taking it for a test ride I could see why.
It was absolutely “done”(and wheezing) at 4500.
It really didn’t do anything particularly well. No great throttle response....... it was just a straight up dud.
I tried a Holley on it, which ran better, but didn’t feel like it made any more power.
It did make the motor behave in a way I’ve never experienced before or since.
After about 3500rpm or so, when you rolled the throttle open, you could feel it lose power....... instantly.
Like more throttle opening was messing with what was going on under the carb.

Once he commited to making some changes, he pulled it out and I dynoed it, just as it was in the car, ex manifolds and all.
It made an earth shattering 283hp. Yeh....... that’s pretty close to 400, right?

Headers picked it up about 30hp,

Changed to a small solid cam, rpm a/g, Demon 650dp........ made another 100hp and pulled strong to 6500.

For a mild street sb Mopar, I like the std performer......on 273’s thru 360’s.

fast68plymouth, based on your story, you and your friend don't have a clue what the SP2P was designed for.

Newsflash, not every after market intake was designed for drag racing, re: high RPM.

The SP2P was made during the gas crisis, when everyone was trying to squeeze out every last MPG from their engine.

It was designed for low to mid range, NOT high RPM, so, it falling on it's face over 5,000 RPM is expected.

Yup......... I’m clueless.

My impression as to the reason behind the OP’s post is that he’s wondering if one of the two manifolds he has on hand offers a performance advantage over the other.
If he really didn’t care about the performance, he would simply put the sp2p back on without giving it another thought.

My story was an illustration as to how much of a detriment to “performance” the sp2p can be.

Look at those runners! Lol

[img]https://www.forabodiesonly.com/mopar/attachments/20170926_183046-jpg.1715095498/[/img]

[img]https://www.forabodiesonly.com/mopar/attachments/20170926_183110-jpg.1715095499/[/img]

[img]https://www.forabodiesonly.com/mopar/attachments/20170926_183126-jpg.1715095500/[/img]

The SP2P wasn't even a decent MPG manifold. I'm sure it's one of those designs that Edelbrock would like to forget about. "Turd" is just the tip of the iceberg. Back in the 80's my local speed shop was having a sale on those manifolds so I bought one for a small block Chevy pickup. 3 days after installing it I put the factory intake back on. Not only did the performance drop with the SP2P, but I lost 5 MPG as well. It's a waste of good aluminum.

Well, alright guys! You guys have me convinced. I’m going to yank the motor to degrease and replace the rear freeze plugs, then I will replace the manifold with the performer

Good choice.

I also made the mistake of running an Sp2p on a 318 but at least it was given to me. I honestly think the car ran better with the stock intake and carb.


Tim

I have bought them at swaps for as low as $20 before just to scrap so it won't be used again

I had a 73 Camaro with a 350 2 barrel. A buddy had a SP2P and a Holley 600 for $35. I saw the chance to swap to a 4 barrel and jumped on it. I know the car was louder when the secondaries opened but I don';t recall if the car was any faster.
Many years later, I put a mild 360 in my 67 Dart. This was a REAL budget build. Lots of junkyard scrounging, etc. A guy in our Mopar club had a LA SP2P for $40. The engine was a reringed 360 with a mild cam. It felt as if it got slower the further I pressed the accelerator. I first blamed the cam, thinking maybe I had installed it a tooth advanced. I stumbled upon a Weiand 4 barrel intake with much bigger ports at a junkyard. The car felt transformed with that Weiand. I am convinced that the design of that intake sucks ass from the crack to the sack.

That’s exactly how that 396bbc felt with the sp2p on it.
After about 3000-3500 rpm, pushing on the gas pedal felt like pushing on the brakes.

As with most things........ if you do some digging around on the net you can find people relaying their sp2p experiences, you’ll find some good and some bad.
Most I saw were negative....... but there were a few who had favorable things to say.

One I saw that stood out(probably because it had a pro and a con) was....... the car picked up 2mpg........ but was gutless.

Tim

The TQ peak of the SP2P is at such a low RPM no TQ converter will stall that low, maybe if you had a crawler that you wanted to idle at 400RPM with a manual trans and never turned over 3500RPM it may be good for that, besides that I can think of no other use.

After driving my friends Camaro with one on it, I came away with the idea that it’s not even intended to be used at WOT.
It’s like the design requires there to be a high amount of vacuum in the plenum(as in throttle blades mostly closed) for it to function “properly”.

In his car, the overall driving experience was poor. There was nothing about how the motor ran that stood out at all....... other than how weak it felt when you stepped on the gas.
One would have expected fantastic throttle response with those tiny runners....... but it was not the case with that 396.
It definitely made the top 10 list of worst overall combos I’ve driven.

I would say a more realistic powerband for one of those is idle to around 2500, with light throttle openings.

Also, obviously since the runners are so tiny, the bigger the motor you put under it, the lower to usable operating range will be.
Probably not totally awful on a 273........to very unsatisfying on a 360.

Sounds like the Offenhauser dual port intake manifold gimmick. It also was a product of the fuel embargo era.

A Mopar engine shop gave me a SP2P for free when I was building a 318 and mentioned I was changing over to a 4bbl. He told me it was a turd. I ebayed it and bought an Edelbrock intake. I still feel bad for selling it instead of trashing it.

I bought one off a guy in my Engine Support Systems Class in college. Gave him 30 bucks for it, his asking price, I didn't haggle.

Put it on the 400 in the C body of the day, with a 750 Competition series AFB from a swap meet LOL.

It was, different. it actually did move the car easier, at tiny throttle openings.

At WOT, "meh" at best. A stock 4V intake would have been better at WOT.

It was a 2bbl motor, Beggars can't be choosers, and 4 barrels is (almost) always better than 2.

It was worth every penny of 30 bucks, though.

I later pulled it, cleaned it up and sold it for 50 bucks.

Edlebrock really screwed the pooch on that design

To the OP .... since MPG is a concern STICK WITH the sp2p IF 90% of your driving is 2800 rpm or less. Now as a lot of NAYSAYERS here proclaim ... it IS a turd intake if you try running over that basic rpm.

It’s a DAMN GOOD INTAKE for what it’s designed for. I have a collection of them still up in Meeeeechigan !

Uhhh...MAYBE under 2500 rpms and UNDER 1/3 throttle.
This is a MOPAR forum, not a Prius forum. Anyone trying to be a "HYPERMILER" here is confused.

Mister pRoCtO ... there you go again- OFF the deep end !

There are peeps here that have stuff - like the OP and me - that have road vehicles where MPG and GRUNT is a concern.... like a truck or a motor home.

Properly geared with a 373 ... I plan on a sp2p with a small TQ on my 2 426w motor homes. Now the one that runs is using a Street Master with the 456.

Doc, Sp2p trying to feed 426 inches in a MH? Your in for hard times, those things are small for a 302 Ford maverik

Seeking torque and mileage is fine, but that plan ain’t happening

N-guy ... but the BB SP2p was designed for bigger cubic inches than a 426w !

You are comparing a 302 sp2p to a 440 sp2p ?

I actually ran one of these for 150K+mi on my '79 Maxivan. Comp RV cam, it was a work truck daily weighing in at 6000+lbs with tools and carpet. The model I had was for the 318 bought new from Summit. They had quit making the 360/340 sized model. With the 2200 stall converter at 50mph it would raise the dash board when the Thermoquad got to wailing. When I sell the van the intake stays with me. It would spin easily up past the cam's RPM range 5200 or so.

I had a SP2P 4bbl intake (they made a 2bbl version too) I sold it to Tony DeFeo for a MPG charger project which I think he never completed.

There is 2 different Performers out there. One has the offset thermostat housing for the newer rotary A/C compressor.