Intake Manifold Options 340

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340swinger4spd

340swinger4spd

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I am finishing a 340 rebuild and need to rethink my intake choice. So the engine is just back from the builder. Stock J heads 2.02/1.60 valves. 9.8 static compression. Cam is a Comp Hydraulic Flat Tappet, Advertised Duration 274/286, Lift .488/.491 230/236 106 LSA 110 center line. 750 holley dbl pumper 4 corner adjustment. 6AL studder box. 4 -speed 3.55 gears.

I have an edelbrock performer but was considering an rpm or airgap. I'm thinking the performer intake will limit me. Any opinions would be appreciated.
 
The performer will work, the RPM air gap will perform better. It will also be a little more cold-blood in the cold weather if that matters to ya
 
340swinger4spd said:
Well, that's hard to say when I don't know how much performance I would get. 50 hp?
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you should be able to get at least 100 out of that 318
:poke:

if you think the airgap is worth the investment, why not sell the performer FIRST and then put in the extra money for the airgap?
(and you don't need a brand new one, they pop up on here from time to time)
 
50 more is unlikely. However the Performer is a smaller port intake which has the 318 port opening. The RPM manifolds are the stock J head 340/360 port size and will perform better overall especially since you are upping the cam timing. Sell one and buy the other.
 
According to this article, the Air-Gap loses a little HP & torque below 3,400 rpm to the Performer, but it's much better through the rest of the range. A little more gear would compensate for any low rpm losses and certainly wouldn't hurt through the rest. A little carb tuning with the change couldn't hurt either. But a stick is more forgiving than an automatic.

Dyno-Testing Small-Block Intakes - Induction Extravaganza - Mopar Muscle Magazine

FYI, the Performer RPM is the same internally as the Performer RPM Air-Gap. As noted earlier, the Air-Gap may not behave as well until warmed up.
 
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IMO the RPM is a better intake than the Performer. Unless you need the heat spend another $15 and get the air gap.
 
Get a grinder and open the intake port up. On something like your engine, if you saw a 10hp difference I'd be surprised, especially if you open the port window and smooth up the port.
 
I plan on throwing Eddie heads on it after my 70 Challenger is finished. Then my little 340 will be a strong runner.
 
All kidding aside..the Air Gap is an Excellent intake i use it on a 360 and 416..as for the Edelbrock heads another excellent choice properly preped they perform quite well..
 
The Performaer is a stock replacement intake and performs as well as a stock intake. The OE intake isn't a shabby part in any form but it is designed as a passenger vehicle part with performance at a level acceptable for the factor to hand out and be fine to warranty it and there engines. They both perform well till 5500 with 6000 pushing it. And I say that only because there are better intakes to use if your going to go aggressive with a cam and to 6000+.

As mentioned above.....
 
Same basic build one has a gasket matched performer 318 the other an RPM

425hp at 5700rpms and 424ft lbs torque
427hp at 5600 and 441 torque
 
crackedback said:
Same basic build one has a gasket matched performer 318 the other an RPM

425hp at 5700rpms and 424ft lbs torque
427hp at 5600 and 441 torque
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And the ootb RPM STILL wins against a gasket matched performer, and even in the performers power band, put some more cam and watch the divide grow between the 2. Performer is more aimed for 5500 rpm and below power.
That test is close only because of the camshaft choice.
 
The cam is BIGGER than the one the OP is putting in his 340... That kind of invalidates your point in THIS case. Smallish cam is cam is not going to have an earth shattering spread, even in OOTB configurations. BTDT

XE268h in a stock headed 340 is all done by about 5500. :)
 
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I personally think the factory cast TQ intake will out perform the eddy performer. I would go with the RPM.

I know people that have spun 7000 rpm's with the factory cast intake.
 
I like the factory intake. Even more so on the bigger engines. The larger port equals more volume easily consumed by the extra cubes and at lower engine speeds. The OE intake is tall by comparo to other makes. It is a very good intake.
 
crackedback said:
The cam is BIGGER than the one the OP is putting in his 340... That kind of invalidates your point in THIS case. Smallish cam is cam is not going to have an earth shattering spread, even in OOTB configurations. BTDT

XE268h in a stock headed 340 is all done by about 5500. :)
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It's all interesting, for that particular build. Now as for apple's to oranges, that's when you modify one intake and not the other and pass it off as a direct comparison. As for the cam, it's not considered big when the motor runs out at 5500 Rpm. But the showing of how close the two intakes CAN be, that's a good build example. I could go on to say turn it up to 6500 rpm and get back to me, but that's not the topic of this thread nor what the op asked.
 
MOPAROFFICIAL said:
Now as for apple's to oranges, that's when you modify one intake and not the other and pass it off as a direct comparison.
Click to expand...

I think Rob brought up gasket matching the performer because the OP already HAS that intake. So, it would essentially be free vs. dropping $300+ on a new intake.
 
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