340 intake or edelbrock performer?

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67valiant

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i have a 340 cast iron intake on my 318 casting number "3462848"
and i have a edelbrock perfromer intake , im putting my j heads on on the 318 casting number "3418915" am i better off using the cast iron 340 intake? i have heard that it is better then the performer, also the ports on the performer dont even look to be the same size, give me you input
 
You will gain little if anything with the 360 head/Performer combo. The Performer has long small 318 type runners. The manifold will be a restriction at high RPM and the larger head ports will cause a velocity drop and hurt low RPM throttle response making the engine feel doggy in traffic.

Stock iron small block intakes were actually pretty good, if a bit heavy. In fact they were probably better than a regular Performer. You'll have enough flow potential for 350 HP easy. Just be careful to raise compression with the larger chamber heads or you'll lose low end torque... making the engine feel doggy in traffic.
 
I would use the E-brock one and save a few pounds off of the front end. Port match it up and it will do pretty good.
 
Performer 318/360 vs 70 340 Cast Iron????

IMHO,

Cast Iron intake hands down, every time, for a performance set up. They are really good manifolds. Put a 1-2" 4 hole spacer on it and go.

That performer intake is a nice replacement for a 318 intake or something like that. Doesn't work as well as the 340 intake in a hopped up situation.
 
Sorry,don't mean to highjack your thread here 67Valiant, but I have a question concerning Crackedback's post there, if someone could elaborate on his suggesting to use a 1/2" spacer on top of the 340 manifold. What is the reason for running a spacer ontop of this manifold? Is it because this 340 manifold is set up for a square bore carb( I think thats what you call a 4bbl with all four barrels/butteryflys the same size )so the spacer gives clearance for the bigger secondaries?? I have this manifold on my 360 and it has a spacer on it, have always not been sure why the spacer was put there. Maybe the answer to this will help you too 67 Valiant, hope ya don't mind:cheers: I'm sure Crackedback could help us out here? thanks
 
Open spacers help HP a four hole spacer helps turque. A spacer is also a good way to insulat the carb. Cooler you can keep the fuel and air the more hp you can make. That is the short answer.

A nother member may be able to go into more detail for you though.
 
Hi thanks for the speedy reply!! I think I remember hearing insulating the carb thing before, forgot about that, didn't know or give anythought to wheather the spacer is open or four hole, not sure what mine is. thanks again....lots to learn here,just need the $$ to put knowledge to useLOL:toothy10:
 
If you look at the 340 intake you will see it has 4 holes in it insted of being open like most intakes. I don't think an open spacer is the way to go with this intake. I tryed an open one 1/2 one on mine but the bottem end went away. A 4 hole might help though.
 
Burntorange70 your still on eh, thanks, hey could ya tell me, on this 340 intake are the four holes all the same size or are the back ones larger, if you know you'll save me pulling my carb just to look out of curiosity. thanks a bunch man!! Hope some of this helps 67val he started this, happy to hear this is a decent manifold to run.
 
It is set up for a square bore carb so the holes are the same size. It is built into the plenum so you will still need to pull the carb to look if you are running a spacer.
 
hey thanks guys,im definitelygoin to go with my 340 intake, i heard it was a agreat intake i just wasnt sure, and macadoo its not problem ur post helped know exactly why i run my spacer now. and also by the way i am goin to a .443/.465 lift cam if that helps with low end torque qwith the j-heads
 
67valiant said:
hey thanks guys,im definitelygoin to go with my 340 intake, i heard it was a agreat intake i just wasnt sure, and macadoo its not problem ur post helped know exactly why i run my spacer now. and also by the way i am goin to a .443/.465 lift cam if that helps with low end torque qwith the j-heads
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That's a good little cam. I have one in my Swinger, idles with a little lump to it. Car ran 101-102 in the 1/4. So it's capable with matching parts around it.
 
I'd open up the ports on the Edelbrock to match your j heads,the weight savings alone over the HEAVY factory piece is worth it...
 
thanks guys, how much does it usually cost to have port matching done?
 
My stock intake on my 340,is set up for a spread bore carb. Currently running a Carter AFB,but had to use a spacer/adapter,or the butterfly's would not open. With a Mopar Perf. air cleaner,I'm afraid it will get into the hood,under tork,so I'm going to switch carbs,to get rid of the spacer. The AFB worked fine on the Eddy. Performer,but I went with the stock one,because of port size. From what I've read on this forum,the stock manifold,will out flow the Eddy. Correct me if I'm wrong.
 
I know a guy with a dart that will be selling a performer in about a month or 2.
If you are intrested.
 
Bigmacdak said:
Define big bucks. $100 bucks $200 bucks? more??
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About $150 for a quality well known porter to do a deep port match. Hughes Engines do deep port matches on manifolds, check out thier prices. It's quite a bit cheaper if you buy the manifold from them, but I really think they would steer you away from a base performer manifold as they are just a step up from the old SP2P manifolds from years ago developed for the GM small blocks.

The cast iron 340 manifold is quite good aside from the weight, as 340s mentioned. If this what you got, run it. I'll take 20+ hp for free over 20 lbs unported. I'll leave it up to you at this point. :read2:
 
i thought about selling both of them but the car is only a drive around town car, but i just wanted that lil get up and go, i think ill just save my money and buy the rpm for my 360 when i get that done, thanks alot for all the help guys
 
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