Small block intake manifolds...

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BoredandStroked

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Hey guys and gals ! I am building a 318 stroker (hasnt decided on 3.578 or 4.00 inch crank yet) and I was wondering what would be a good manifold. I have cut it down to 4 that I think would serve the purpose and get me the horsepower I want. I am hoping for 450 +/- horsepower in this lil combo.

The manifolds that I have picked so far are the: Weiand X-CELerator, Weiand Stealth, Edelbrock RPM Air-Gap, or Mopar M-1. I have never seen any Weiand on a mopar yet and I am curious at how well they perform. I was looking at the "basic operating rpm range" of all of them and the X-CELerator is claimed to have a 1500-7000 basic operating rpm range or Borr for short. The Weiand Stealth is claimed to have a Borr from idle to 6800 rpms. The Edelbrock comes in with a 1500 to 6500 Borr. I didnt get a Borr for the M-1 however so forgive me.

I plan to set the rev limiter between 6500 and 7000 so which of these manifolds would give me the most horsepower but also a flat line of torque since I will be running on the street quite a bit. Well any help will be greatly wanted and thank you all!
 
remember the more stroke you go, the less high rpm's you have. the cam powerband will help decide the borr. most streetable cams stop at about 6500.
 
Manifolds... I really want to know if anyone has heard of the Weiand's being run on a Mopar before. They seem like a good manifold on paper... but that doesnt always mean they are good on the street. The M-1 was my first choice because I have heard nothing but GREAT news of it. I am just not sure of what manifold would be a good choice due to the crankshaft really.

The comment in the article... "Why build a 318? Some may argue there is never a reason to build the Mopar 318." Here is my reason... imagine going to a car cruise and when you get out of the car you hear people saying "He has a 340 under there pumpin about 500 hp." Then you tell them its a 318... Now that my friends is what Mopar is all about... surprising the S**T outta those chevy and ford boys.
 
B&S;

The only time I seen one of the Stealths on a MoPar was on a 318 in a old freinds Duster. ('73) The rest of it goes like;
.030 overbored 318
small Carter
MoPars 280 duration cam and Mopar headers.
904 tranny and 3.55's to the tune of 13's in the 1/4.
 
Well would you say it was a good manifold? How much of a difference in power did it make or how much better did it work in the 1/4 mile? Thank you RumbleFish360
 
There wasn't a comparo done on it. I didn't run it. I didn't own it. Sorry I can't help with a been there done that. The owner liked it. It seems to be a square bore, holley bolt pattern only version of the action plus. Take a look at it at the Holley web site. The above 318 was a 9-1 engine.
 
I'd be looking at either the RPM Air Gap, or the M1 single plane. AG for the 3.58 stroke, M1 for the 4". Basic operating ranges get shuffled around when the stroke changes. All numbers go down when it's increased. You want to be careful with head choice too, the bore will seriously shroud some head/valve designs...
 
AG? I havent heard of them but I will check them out. I will probably go with the M-1 and port it out a lil bit or just bolt it on. All depends on money and how much hp it will give me. Which is only like 5-8 hp at the most. If I can run 11s when its all said and done... then you all will see the happiest kid on the block ever. Which kind of head do you think is the best for a 318... Moper? Thanks all!
 
AG is the Edelbrock Performer RPM Air Gap Moper is referring to. It is basically the Performer RPM with a tunnel underneath the plenum which air can flow through.
 
In terms of cost vs. return on investment, I dont think you could go wrong using Magnum heads with the 3.58 stroke. They'll move enough air to feed it decently and reach your goal, with a little port cleanup, for minimum investment. The MP Magnum R/Ts would be a step up from that, with more potential, but taking more $$. Price wise, unless you can get the MPs cheap, Edelbrock RPMs wouldl be a even stronger possibility for roughly the same $ spent. If you run Magnum design, you need AMC lifters and Magnum pushrods, and the LA intake manifold pattern drilled into them, so those should also be factored in when thinking about which gives the best for the least $. If you happen to start with a Magnum 318 core, you also have provisions for a hydraulic roller cam, but you'll have to run an electric fuel pump. If you go 4" arm, I wouldnt use the Magnums or the Magnum R/T heads, go straight to Edelbrocks.
 
Wow now that is alot of power in that 318. I have seen race block 2 bolt mains (dontk now why they didt go for 4 bolt) make over 600 hp... now thats nuts. Plus it was a chevy... maybe thats why they went with the 2 bolt mains and not the 4 bolt... kind of on the "special minded" side. Thanks 388Dart
 
MoPar blocks, stock units, can handle lots of power without the need of 4 bolt mains like a Chevy does. However, it is a bennifit to have a 4 bolt main for your engine. At your level, you'll not need it so long as you don't beat the stones out of it or constantly go to really high RPM levels.
You'll have a long life engine if you keep it under 6500 RPM's.
 
So your saying to set the rev limiter at 6500? If it spins that fast after I stroke it of course. I knew 2 bolt mains could handle alot of power but... 600 hp? I never thought they could handle that much. Oh... isnt everything from Mopar the best? Haha... dont compare royalty to junk there dude... Mopar and Chevy? Come on now Rumblefish360... haha just kidding! Thanks everyone!
 
I'd stop the use of the 2 bolt main around 525 HP. Though it can take more, I wouldn't push it. A safe than sorry thing.
I also bet with the increased stroke, you'll make peak power abit before 6500.
 
Ok I was thinking I would make peak power before 6500 anyways if I went with the 4 inch stroke. How many more rpms after peak power should I set the rev limiter? Or does that bepend on how fast or slow the power drops after peak power. Thank again!
 
That depends on your rear gearing, and convertor. I try to get the setup so I'm a little over peak horsepower at the stripe. The limiter can be set for anything over that you feel comfortable with. If my peak was at say 5900, and I'm crossing at 6100ish, I'd be chipping the limiter at 6400.
 
OK thanks... I am settling on the Mopar Performance M-1 intake. I will just see where I am making peak power once the whole engine is built and I have it dynoed then set the limiter. Thanks!
 
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