383 Engine carb/cam upgrades - newbie

[BIGBLCK11]

Hi All, I need some advice on engine upgrades.  I am a newbie to Mopars and by no means an engine tech.  I have read through many posts on 383 builds here, but they vary per application of course.  So, I figured I might as well just post mine and see what you recommend.  This is for my 70 Charger, that came with a rebuilt stock 383, .030 over flat top pistons, 2bbl carb, 2.76 open rear, 727 auto on the column.  I have already replaced the intake /carb with a eddy RPM and an eddy 750.  I swapped out the diff with a 3.73 truetrac(Thanks DoctorDiff). The rear  tires are 27" tall.  I have a rebuilt 833 4spd, std ratio(Thanks Brewer's) and most of the parts to convert the tranny, so it will be a stick by winter(I hope).  I also have a set of 1 3/4 Doug's headers for it.  The car was not running great with the 1411 carb, which I have since read(too late) is not favored by many on here.  I guess they can be setup with enough tinkering, but after reading all the posts on hard starts when warm  and off-idle stumble,  I do not want to mess with it.  It did run a lot better with an eddy 600 that my brother loaned me.  I thought maybe the 750 was just too much carb, but I have seen a number of posts on running a Holley 750 DP on a stock 383.  I want to make the switch to a Holley double pumper, but thought a 650 or 700 might be better.  I am also looking at cams.  I have read good things on here about the Lunati Voodoo 60303 cam.  I am debating on going the extra mile and getting the RPM 84cc heads. 68Blue's combo sounds pretty good (84cc heads,RPM intake,750 DP,Comp 21-223-4) My main question is which carb/cam combo to go with if don't swap the heads and which combo if I do?  Can I get away with a carb/cam combo that will let me just upgrade the heads later or will def need a bigger cam at the point I move to the better RPM heads? I want the bottom end power and a lopy sound like others, but with some street manners.  I just cruise it, not a track car, other than maybe to get some times at some point.  I am sure the heads would make a big difference, but it is quite a bit extra to spend for my usage.  Of course, we all end up wanting more power, right?  All input is greatly appreciated.  I will post some pics of the car soon. Thanks, Len.

[mhinders]

Well, I can tell you my current situation...having a 67 Charger with 383 and auto.
Previous owner bolted on Eddy RPM intake, Holley 750 w vacuum secondaries, and a Comp-cam giving low vacuum and powerless, lumpy idle. Unfortunately the type of cam is unknown at this moment.

The engine needs certain rpms (>1500) to start functioning properly. That's close to ok for the highway, but slow cruising on a Sunday afternoon is a pain, running the risk of fouled plugs...not to mention the powerless brakes...
Looking carefully at the plugs I can see that the combustion is very uneven between the cylinders, a couple of cylinders running lean, and some rich, and overall bad mix of the mixture in the cylinders, a very undesirable situation. I'm getting 13 mpg on the highway with standard rear (2.94?)
I assume all this is due to the combination of standard heads and "big" cam+intake+carb. Some aftermarket better flowing heads might improve the mixture distribution in the cylinders, at least for open throttle driving...

Depending on how you plan to use the car...for cruising don't go too "big".

Cheers,
Martin

[doctor4766]

Interestingly enough, I also had issues with a cam recently. It was a MP 383/440 resto Magnum cam that we fitted in my 383.
Very low vacuum and running extremely rich. Couldn't get any more than 8" of vacuum.
We ended up rebuilding the motor and used that same camshaft since it was almost brand new.
Still ran the same until we swapped out the cam for a Crane. Runs very nicely now.

Turns out the MP cam was incorrectly packaged and I was given a 509 lift instead!!! 
I'm still in the process of trying to get a credit from the supplier but of course even a coupla hundred dollar credit wont make up for all the headaches and time we went through trying to work out why the hell this thing ran so wrong.

[Nacho-RT74]

Turns out the MP cam was incorrectly packaged and I was given a 509 lift instead!!! 

[BIGBLCK11]

Yeah, I am guessing both of the cams I listed are too big without doing the heads too.

[BIGBLCK11]

Any suggestions?  FireFighter3931, Your input would be greatly appreciated.

[Sixt8Chrgr]

Take a look at the Comp Cams Extreme Energy 268H.

[BIGBLCK11]

Hi, Thanks for the response, that looks like it could be a good choice.

[Al]

I'm very happy with the Lunati Voodoo 60303 cam, Eddy Performer RPM heads, intake and TTI headers in my 383. Really woke up the beast.

[firefighter3931]

Cam selection is difficult without knowing the exact static compression numbers. It's easy to overcam a low compression motor and make a slug out of it. On the plus side you have a 4 speed and 3.73 gears so that will help mask a potential deficiency. 

I would look at an Engle K56 for that combo 


Ron

[BIGBLCK11]

Al - Thanks for the input.  I read an earlier post of yours and you replied to a pm, that you run the 670 Street Avenger carb.  It sounds like a great combo.  I am just really debating the extra cost of the heads.  If I go that far, does it make sense to find a 440 to swap in?  It is the numbers matching motor and newly rebuilt, I didn't want to just swap it out and put it under the bench forever.  I don't expect to be tearing it up, so I thought the heads would be a good way to get more power with what I have.  Did you have any thoughts of moving to a 440 vs the upgrades you did?  Obviously, the 440 swap isn't just a direct fit and I already have upgrades for the 383.

Ron - Thanks for the advice.  BTW, the Black Pig looks awesome on the PINKS thread. I am sure you'll get 'em next time. After that heck of an adventure, I am glad you still enjoyed it.  On the combo, I also do not want to over-carb it, do you think a double pumper is necessary?  I will prob. still swap the Eddy for a Holley, you think 650 or 700? Double pumper or not?  I was told it was good to go with mechanical secondaries on a 4 spd car, but also the vacuum secondaries are nice for the street.  This would be without the RPM heads

Len.

[firefighter3931]

Hi Len, thanks for the nice remarks. It sure was an adventure, lol 

For your build i would definately go with a double pumper. The Proform 650cfm "street series" carb would be my first choice. Once you get it up and running we can work on tuning it for max performance. 


Ron

[BIGBLCK11]

Thanks for the replies Ron and everyone.  You guys(and gals) are all very helpful on here.  It is such a great forum!  I will keep you posted on what I move forward with. Len.