Which intake would you use?

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mopar56

mopar56

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So not really an A body question but sort of, you see the engine came from a 70 Dart with 12,000 org miles I've had it for many years and it is in a 56 Dodge truck hot rod project the motor was a factory 2bbl which is still on it but I am swapping to a 4bbl, I have both of these intakes, the dual plane says 318/360 on it the single says 318 street master I have posted pics of the ports, the truck will be very light, S/B utiline with a a833 from a 69 Cuda the rear is a 3.23 ratio, I do not plan on doing any other work to the motor except maybe a mild cam it is currently stock. The use will be strictly cruising , some hwy, no 1/4 mile stuff. So your thoughts???

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I don't know much about the 318 street master but I have used the performer on a 318 and it works very well and has the 318 port size. 600 carb would work well and are cheap used. Eddy or holley. Or even a good thermoquad.
 
I have heard the the 318 single plane street master are not worth their salt. They tried making an economy 4 bbl manifold for the 318 in the fuel crunch days and it did not work out very well.

There are a million cams to choose from. I like using the mopar 340 cam as the baseline to compare to. Melling makes about the same grind for half the money than mopar performance : melling SP-22
 
What engine? You failed to mention that. I think either way though, I would go with the Performer. It's a pretty good one.
 
I'd use the dual Plane and a 318 Thermoquad on that spreadbore manifold
else an AVS
note how it has been installed on smaller port heads
no biggie for your application
timing chain good?
Ask AJFormS about that 340 cam in your application- I'll post something later tonight
keep on truckin
 
If you have a 318 or 273 I would go at the street master, if you have something bigger go with the performer..
I had the street master on a 318 with a Holley 600 and it worked great..
 
good point J-Par
those that did not like that manifold were trying to make horsepower especially with 360s
 
Ok thanks for all the good post so far, I tried to give all the info pertaining to the application and cant believe I did not post engine size...sorry, it is a 318, the last of the higher compression motors hence why I chose it but if course smaller vakves which is why I was leaning towards the Streetmaster, my spine had the dual plane one on his 80 pick up 318 and it worked well but he had the swirl point heads, as for carb I have a 600 Holly and a Eddy 600 to I'm not positive which I will be using yet.
 
The street master has true 318 sized ports. It’s a single plane but the runners are small so it maintains good port velocity. I ran one on the 318 in my Challenger with a 600 cfm Edelbrock and headers. It did fine for what it was, that intake is a good match for the stock small port 318 heads and small valves.

That said for a truck I would still be inclined to run the dual plane for low end performance. With a stock or close to stock 318 though I’m not sure you’d notice much difference between the two.
 
Well if I remember correctly usually when you ordered SBD gaskets you got the blue soft composite gaskets for the 360 and thin metal compression style gaskets for the 318 but I would always use the composite style for the 318 when using g a 4bbl intake, it's been a few years, dose that sound correct?
 
IIRC, I had read the street master was designed for stock engines and increased mileage. Does anyone know exactly how it was marketed?

Oh, I’d use the Performer.
 
Since you’re running a 4 speed I’d put the Streetmaster on it. The performer would probably be a little better off-idle but with a manual transmission that doesn’t really apply. If you get bored you could open up the plenum a bit just below the carb pad.
 
Composite gasket, never been a fan of the steel intake gaskets.
 
Steel is for steel on steel you do not want to use anything but a thick composite gasket for an aluminum intake as it heats and cools at a different rate then the steel...
 
Post a side shot of the shitmaster intake.

You could take it into a machine shop and ask them to cut the plenum open another 1" or so to make it work another 1500 rpm higher in the power range...ooorrrr You could also just use the performer that will carry as is to about 5500 and then flatten out and dip by 6000
 
The last photo is a side shot of the streetmaster I'm not at home now so cant post another right now, I'll probably never push this thing past 6 grand anyway, one thing im going to do once I get the old manifold off is try both of them with carb and air cleaner loosely as I have a bit of a height issue to and the street master looks about 1 inch lower, however if that dosnt affect things I'm leaning towards the performer, i will use composite gaskets I knew there was a reason good point on the expansion and cooling with aluminum compared to cast steel, thanks. I probably wont bother changing the streetmaster to improve performance when i could get the same results it sounds like from the performer if it clears ok.
 
IMO the Street Master may have been better than the OEM iron 2bbl carb and intake back in the day, but the Performer will out shine it everywhere with no down side.
 
Hang on guys; with a manual trans, the engine is married to the tires.
The starter gear in this instance is 2.66x3.23=8.59, which is brutal for a 318 to pull.
If it had an automatic, then it would additionally have the TM (Torque Multiplication) from the TC which at zero mph can typically be plus 80%, and diminishing rapidly with speed to something like plus 40%, eventually hitting a low of perhaps plus 8%.
Furthermore, the automatic is never required to pull hard below stall.
But with a manual how do you drive below 30 mph? with 3.23s ?
I'll tell you; with 27" tires; 1000rpm is already 9 mph. Think about that. 20 is 2135, and 30 is 3200. So every time you slow down, you are gonna be in these ranges.... in first gear. So if you want to accelerate from those rpms without bogging or hesitating with the 318, this demands low-rpm torque, or a slipping clutch.
Low rpm torque with a given engine requires cylinder pressure and the air has got to speeding thru the intake to get to it's destination, especially at low throttle openings, keeping it's fuel load in suspension.
OP says the engine is a 70, so it does have some compression, and the cylinder pressure on those is a lil higher than the smoggers. That means, the intake is the second last tool to making torque, the primary venturi size being the last. Since the performer covers both bases, to me it's the logical option.
Those 3.23s are gonna dictate the choice.
Now we get to OP's stated useage; namely cruising.
With 27"tires, 65=2610. With a hi-compression 318, and proper timing (which could be in the 50s), the throttle opening is gonna be pretty small. Now the smaller runners are really gonna pay for themselves, with runner velocity, keeping the AFR relatively stable at cruise. And that means you can lean it out, and that means more miles per unit of fuel used.
 
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