Weiand Action Plus any power gain over factory 340 ?

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Dustine

Dustine

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Is there any noticeable low end power gain going from factory cast iron 1972 340 intake to a Weiand 8007 Action Plus ? My car is a bone stock 72 340 low compression cast crank factory exhaust manifolds small port heads 904 auto . I am in the process of switching the 3:23’s to 3:73’s from Dr Diff . Other than the wait savings is it worth the switch to the Weiand ?
 
In my humble opinion, no.
The Weiand is a good street manifold, but the factory one is an excellent design right off the bat. I don't think you would see any noticeable seat of the pants benefit, outside of the weight savings.
 
Professor Fate said:
In my humble opinion, no.
The Weiand is a good street manifold, but the factory one is an excellent design right off the bat. I don't think you would see any noticeable seat of the pants benefit, outside of the weight savings.
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Thanks Professor maybe I will put the money towards a good set of headers down road instead of a new intake
 
Isn't a Weiand 8007 a small port manifold? I thought it was comparable to an Edelbrock LD4B, and Weiand had another dual plane that was more comparable to an LD340.
 
72 340's used J heads, not small port. Smaller 1.88 intake valves are the only difference. You will see a power loss when you swap out that intake and the 72 340 TQ.
 
JDMopar said:
Isn't a Weiand 8007 a small port manifold? I thought it was comparable to an Edelbrock LD4B, and Weiand had another dual plane that was more comparable to an LD340.
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66fs said:
72 340's used J heads, not small port. Smaller 1.88 intake valves are the only difference. You will see a power loss when you swap out that intake and the 72 340 TQ.
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Yeah, good points- the Stealth is the bigger port manifold, and I believe you're both right- Action Plus is 273/318 port size.
 
Thanks guys I was confused between the Stealth and Action Plus . Do you think if I used the Stealth it is still not much of noticeable difference in power gain compared to the factory intake ?
 
An Edelbrock Performer RPM or LD340 would be the only two possible upgrade manifolds, but I think the gains would be so slight that you wouldn't notice much difference, especially for the price. The RPM would require a divided or four hole spread to square bore or if you retained a ThermoQuad.
 
Stealth or at least the one I have from 1997ish had small ports. They taper down to the window so they can easily be opened up to 340/360 size ports.

If its together and not leaking or has any other issues then yes money is better spent else ware. Even headers would be questionable if you have 340 HP manifolds.
 
You might even see a loss. It's not that the Weiand sucks, the stock 340 intake is simply that good.
 
The best performance dollar spent on the late ‘72 to ‘73 340 is an increase compression. Especially if it’s aluminum heads with a set of head gaskets that make quench. It’s just a shame it takes so many of those “performance dollars” to do that (if you can find any aluminum heads right now!), and it takes more restraint than most folks have to keep it from turning into a rabbit hole. Oh, BTW, that’s a nice looking ride, a personal favorite of mine!
 
Dustine said:
Is there any noticeable low end power gain going from factory cast iron 1972 340 intake to a Weiand 8007 Action Plus ? My car is a bone stock 72 340 low compression cast crank factory exhaust manifolds small port heads 904 auto . I am in the process of switching the 3:23’s to 3:73’s from Dr Diff . Other than the wait savings is it worth the switch to the Weiand ?
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When it is in the cards, I HIGHLY recommend the Eddy Air Gap. Noticeable increase.
 
Dustine said:
Is there any noticeable low end power gain going from factory cast iron 1972 340 intake to a Weiand 8007 Action Plus ? My car is a bone stock 72 340 low compression cast crank factory exhaust manifolds small port heads 904 auto . I am in the process of switching the 3:23’s to 3:73’s from Dr Diff . Other than the wait savings is it worth the switch to the Weiand ?
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I can’t say I’ve ever read any articles, posts or test results comparing the two. You’d probably have better low end up to low/mid range with the iron but better mid/upper and upper range with the Weiand. The Weiand is a high-ruse and has better radiused turns etc etc. I’d clean up what you have at the most and run it.
 
Thanks for all the great information guys . I just got offered a Edelbrock Air Gap 7576 for a very low price from a Ford guy who happens to have one . He is going by the numbers on the box it’s in . I’m just waiting for him to verify the part number stamped on the manifold .Do you think an Air Gap on a stock 72 340 engine is worth it ? If not I may just grab it for later down the road when the engine needs a rebuild and I can build more of a performance based street bruiser .
 
Dustine said:
Thanks for all the great information guys . I just got offered a Edelbrock Air Gap 7576 for a very low price from a Ford guy who happens to have one . He is going by the numbers on the box it’s in . I’m just waiting for him to verify the part number stamped on the manifold .Do you think an Air Gap on a stock 72 340 engine is worth it ? If not I may just grab it for later down the road when the engine needs a rebuild and I can build more of a performance based street bruiser .
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Are you running A/C? I don’t believe factory brackets will mount up if it’s still in place, or clear the compressor? The Weiand I know will accept the factory mount point and clear
 
The stealth 8022 has the same port window as an Act+ 8007 1.00x1.96

Funny that an LD4b runs really well on a 340...
 
I wouldn't use a stock Air Gap on...any engine that is...stock. The RPM range is 1500-6500. All else being equal, the AG will slow the car down on a stock 340. The Perf [ or Weiand equivalent ] is the best choice.
 
Dustine said:
Thanks for all the great information guys . I just got offered a Edelbrock Air Gap 7576 for a very low price from a Ford guy who happens to have one . He is going by the numbers on the box it’s in . I’m just waiting for him to verify the part number stamped on the manifold .Do you think an Air Gap on a stock 72 340 engine is worth it ? If not I may just grab it for later down the road when the engine needs a rebuild and I can build more of a performance based street bruiser .
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RPM air-gap is the best dual plane intake for a SBM. Grab it. Can't imagine it could hurt performance even on a bone stock engine.
 
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