Stock intake vs performer?

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Why not just go with an RPM or Air Gap, and be done with it ?

Put that Performer on a teen project, and use that old iron piece for a boat anchor.
 
66fs said:
You guys keep worrying about 25 pounds on a 3,400 pound car and keep giving up .2 in the quarter because your in love with aluminum???
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Not sure if worry is the right word, but 25lbs off the nose of my car sounds good to me.

.2 ? Not sure where that came from.....But ok.
 
Johnny Dart said:
Why not just go with an RPM or Air Gap, and be done with it ?

Put that Performer on a teen project, and use that old iron piece for a boat anchor.
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Cause ain't everybody got 350 dollars?
 
Check out Vizard's book "how to build horsepower" (?) he massages a stock 4bbl chevy iron 350 intake and makes it work better than ANY aftermaket intake on a stock 350...just a die grinder and a little cleanup work. Induction on a stock motor is pretty forgiving, but the Edelbrock is probably 60% lighter. Most stock Mopar 4bbl intakes are of a very good design.
 
Johnny Dart said:
... .2 ? Not sure where that came from.....But ok.
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Both "69Cuda440" and "318Willrun" Posted .2 minimum reduction in 1/4 mile ET for the cast iron boat anchor compared to the Aluminum Performer. My only point is, weight is not everything.
 
71dusterdan said:
... Only question left is which heads? My J's or my magnums. That will depend on pistons and condition of both sets of heads. For obvious reasons I am hoping the J's are good, and I can find a piston to work...
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I've never seen a cracked J head, good luck with the magnums. I would definitely Magneflux the Magnums.

The opened up Plenum on the stock intake is for a little more power at higher RPM.
 
66fs said:
Both "69Cuda440" and "318Willrun" Posted .2 minimum reduction in 1/4 mile ET for the cast iron boat anchor compared to the Aluminum Performer. My only point is, weight is not everything.
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My point : Put on a RPM or an Air-Gap, and this discussion is a moot point.
 
71dusterdan said:
So after really spending some time comparing the pics posted of a stock intake and the massaged one, was there much benefit to be had carving up the plenum? By the way, you guys are turning me to my stock intake. Guess the performer will be for sale soon. I'm going to throw that mopar crank with the 340 journals and 360 stroke in it, keep my XE268 cam, and TQ. Only question left is which heads? My J's or my magnums. That will depend on pistons and condition of both sets of heads. For obvious reasons I am hoping the J's are good, and I can find a piston to work. Thanks for the intake help.
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Opening up the plenum will help above 5k I would leave it for the street and just run it stock with a 1/4" plastic spacer that usually comes in the rebuild kit for the carb. The pics of my intake look like a simple gasket match and carving of the plenum but in reality there is about 25 hours of porting, shaping, measuring, short turn work, wall work, and acid porting. This was for a F.A.S.T. Engine I was and may still do when I win the lottery.
 
66fs said:
I've never seen a cracked J head, good luck with the magnums. I would definitely Magneflux the Magnums.

The opened up Plenum on the stock intake is for a little more power at higher RPM.
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I have a couple of cracked J heads. One set had 7 of 8 cylinders cracked.
Some had several cracks in the same cylinder.
 
Johnny Dart said:
My point : Put on a RPM or an Air-Gap, and this discussion is a moot point.
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If a Performer is not as good as a stock 340 manifold, and a Performer Air-gap beats a Performer by approximately 15 to 20 Horsepower throughout the range between 3K to 6K, then if you split the difference for the stock 340 to 8 to 10 Horsepower gain between the 3K to 6K range, The difference is not worth my time or money to change to a Performer Airgap for the street. I can easily make that up elsewhere, especially if I can run my TQ.
 
66fs said:
If a Performer is not as good as a stock 340 manifold, and a Performer Air-gap beats a Performer by approximately 15 to 20 Horsepower throughout the range between 3K to 6K, then if you split the difference for the stock 340 to 8 to 10 Horsepower gain between the 3K to 6K range, The difference is not worth my time or money to change to a Performer Airgap for the street. I can easily make that up elsewhere, especially if I can run my TQ.
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If you took the performer 318/360 and opened the runners to ld/rpm/ag sizing, it's a dead heat on peak HP in most every case. The Ld4b with those 318 ports runs right with an ld/rpm/ag.

There isn't much difference in any of those intakes for peak HP when the openings are the same. If you have an LD340, it's a waste of time and money to get an AG intake. Block the heat riser and run the LD340

The performer 318/360 is supposed to be the low rpm intake making better tq according to some, yet the LD/RPM/AG all made better tq throughout the range on those 425ish HP 360. Some of the difference may have been differences in carbs when tested.

Intake air flow and port sizing isn't that important on most of these engines. There are many cases where an intake flowed more air than a different intake on the same head. The one that flowed LESS air kicked the snot out of the big air mover. It's the combo. Look at the super victor, without serious work, it's a dog of an intake yet flows a lot of air.

Another is the mismatch of putting a 340-360 sized intake on 318 heads... it's not that big of a deal and way overblown as a giant taboo.
 
jacksdodges said:
So is the LD 340 better than the air gap intake ?
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Edelbrock #LD-340

Good enough to set the NHRA 'SS/IA' National Record in 1972.

For 'general' Street ~ Strip Performance, nothing beats the #LD-340 with it's
Dual-Plane ~ High-Rise design.

$_57.JPG
 
fratzog lover said:
AIV, gkmopar has an airgap intake listed now for $200.
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Thanks for the heads up Fratzog. I think I'm going to go with what I have for now and look at changing things up down the road. My Ride is built for street fun and I have no doubt that it will be just that.

Coincidentally, down the road might not be too far away.. out of the blue I'm talking to a guy about my car and now I may have a lead on a complete Sixpack set up at a real good price. IF it turns out to be a real than I will be selling an unused performer and Holly Avenger.. lol

AlV
 
crackedback said:
If you took the performer 318/360 and opened the runners to ld/rpm/ag sizing, it's a dead heat on peak HP in most every case. The Ld4b with those 318 ports runs right with an ld/rpm/ag.

There isn't much difference in any of those intakes for peak HP when the openings are the same. If you have an LD340, it's a waste of time and money to get an AG intake. Block the heat riser and run the LD340

The performer 318/360 is supposed to be the low rpm intake making better tq according to some, yet the LD/RPM/AG all made better tq throughout the range on those 425ish HP 360. Some of the difference may have been differences in carbs when tested.

Intake air flow and port sizing isn't that important on most of these engines. There are many cases where an intake flowed more air than a different intake on the same head. The one that flowed LESS air kicked the snot out of the big air mover. It's the combo. Look at the super victor, without serious work, it's a dog of an intake yet flows a lot of air.

Another is the mismatch of putting a 340-360 sized intake on 318 heads... it's not that big of a deal and way overblown as a giant taboo.
Click to expand...

Thanks for your real world experience.
 
Any difference between a 71 and 72 stock intake? My intake is number3614025. Also where do you find the casting number on the crank? Better see if I have any more surprises. My blue late 71 block has orange J heads with 1.88's, I swear I will puke if I discover a cast crank! The parting lines look good and the balancer is a forged crank piece.
 
Forged cranks do not have casting numbers. The parting lines are wide, inch or two. Casting lines are very thin. 72 is a good Intake. 1.88 are good also.
 
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