Edlebrock 9905 600 cfm Vs. Edlebrock 1805 650 cfm Vs EdleBrock 9907 750 CFM

[moper]

If you use the later intake, any Edelbrock carb will bolt up. The earlier one uses a narrower patter that even the Edelbrocks won't fit. Avoid the adaptor if you can.
On the cam - great choice. Comp makes great products. Another economical choice would be the Summit Racing branded "small" cam. It's smaller than the Comp XE268 but makes great power. It's also a bit cheaoer. Buy a set of MP springs and run it. I like a 600-700 carb for a 383, especially a milder one. So the 650 Thunder AVS would be my first choice.

 

[70bigblockdodge]

I agree with moper I like the thunder series better because the spring loaded air door on secondaries is easier to tune than adjusting weight on counterwieghted door in afb style edelbrock, which also makes a 750 work on a 383.

 

[mrzods13]

Ok sounds good I will go with the thunder series, I did notice the kit says adjustable valve train required but I am not sure, when you read the cam specs it has notes but the number isn't next to the full kit that I bought , do I need to purchase new rocker arms with that kit, I bought it already but if I have to buy rocker arms I will look at something else and return it being the kits comp cams sells are around $1000. Here's a pic from the c cams website for this kit I bought.

 

[moper]

The XE268 is a great cam. Reason being - it works with the stock manifolds and convertor, and doesn't require major mods like double springs and adjustable rockers. "Require" being the key word there. It will work with the std performance type lifter (the 822-16 for post '68 big blocks) but you want to make sure you have adequate lifter preload with whatever pushrods you use. The "step up" is the anti-pump-up lifter (867-16) that requires much less preload and has no real room for error there - so you have to have an adjustable rocker system with them.

 

[mrzods13]

So it isn't necessary to use an adjustable rocker system only if they include 867-16, it doesn't say which lifters it comes with which is why I am a little confused, I am still learning so excuse my confused mind it will clear up eventually, just don't want to screw anything up. So my interpretation of the listing is that if there is no installation note next to the kit then I should be good, so I also don't have to machine the cylinder heads either, the listing I looked at to buy said in big bold letters that machining the heads is required.

 

[70bigblockdodge]

The machining they are talking about is for the valve guide area to use a smaller dia or double springs which requires the smaller dia seals. Just use the first spring they recommend the 911-16 works with stock seals, the only issue I had with them was dia trying to use stock retainer, trying to be a cheap a$$, the retainer they are recommending is a 10 degree and if your keeping the stock valves they won't be single groove so you can't use their retainer I used mopar performance retainers but that is more expense, moper might have detailed answer.

 

[mrzods13]

I called comp cams and they said that the k21-223-4 kit doesn't need machining, I guess the kit doesn't come with the parts that have the notes next to them, if I bought the recommended parts then I would have to do it like you said, didn't doubt you guys thats why I came on here first because of experience you might have had or problems you ran into. I don't know how good the techs are at comp cams but figure I would call and ask.

 

[mrzods13]

With the intake I was reading an article in mopar magazine where they did pretty much the same thing I am doing and they said they used to grind down the center of the older intakes so each cylinder would see all 4 barrels instead of two. Think I can get away with doing that. Maybe I can notch out a small section. Here is the article http://www.moparmusclemagazine.com/..._1303_c_body_383_bolt_on_and_go/photo_06.html

 

[moper]

I was going to say - Call Comp and ask what the kit comes with...lol. Like was said - "machining of cylinder heads" applies to certain valve springs. The cams bigger than the 268 may mandate those springs. It also could refer to retainer to guide clearance but not until you start getting a bit bigger in cam lift.
In terms of the intake mod - it's been around for years. I think it's in the various early MP manuals too. With a dual plane the carb's size if effectively halved which means the signal strength is much stronger. That's part of the reason a dual plane will usually make more torque at low rpm. But because the carb is effectively "split", the engine also is more quick to reach the limit where the horsepower is as high as it can be for the amount of carb it has access to. That is to say it runs out of breath quicker, at a lower rpm. By cutting that passage you allow the signals from the opposing cylinders access to the entire carb. that "fools" the carb into thinking it's bigger than it really is, and that adds horsepower and rpm with no appreciable loss of low end torque that might be felt with a single plane intake. That's one of the reasons the RPM is such a great intake over such a wide range of rpms.

 

[mrzods13]

Yea the only thing they said was they couldn't tell me what pushrods to get to see when I get to that point. Where about should I make the cut. I would really like to take the heads off and replace the gaskets and maybe do a valve job, but i am sure I am opening a can of worms.

 

[mrzods13]

The machining they are talking about is for the valve guide area to use a smaller dia or double springs which requires the smaller dia seals. Just use the first spring they recommend the 911-16 works with stock seals, the only issue I had with them was dia trying to use stock retainer, trying to be a cheap a$$, the retainer they are recommending is a 10 degree and if your keeping the stock valves they won't be single groove so you can't use their retainer I used mopar performance retainers but that is more expense, moper might have detailed answer.

The valves on my 383 are 2 groove and 4 groove and the retainers they sent me in the kit will work. The exhaust is 4 and the intake is 2. The engine was rebuilt by the previous owner, the motor is spotless no sludge or any kind of build up. Maybe he had the valves down, but I did take two retainers off and they are 2 and 4 groove so that's a plus.