383 cam/ setup help

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schmitt

schmitt

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Hey guy's

Hoping to get some help on my setup with my 69 Dodge D100 (383) . My power doesn't seem to come on till 2800-3000 rpm, then it starts to really go. Thing won't brake stand for nothing, just seems dead down low. Thinking it might have the wrong cam for me. I'm looking for low end/midrange power.

383bb out of a 70 road runner. (Rebuilt not long ago) guessing 30 over
Weiend action plus intake
Flow tech headers
Fast ez Efi
727 auto with Saturday night special converter (1800-2000stall)
Dana 60 3.54 open. Will be adding sure grip

Thinking of maybe going to the Edelbrock performer plus (idle-5500rpm) I'm hoping I can still keep the idle lope I have now. (Guessing the cam now is close to stock specs in the 70 roadrunner)

Thanks for any advice
 
Lunati makes a Voodoo cam with 256/262 specs thats probably a better choice than the Eddy. Any idea on the compression/ heads your engine has? Make sure your distributor is functioning properly and timing is in the ballpark before you do anything. Ignition causes many people to spend more money than they usually have to.
 
fratzog lover said:
Lunati makes a Voodoo cam with 256/262 specs thats probably a better choice than the Eddy. Any idea on the compression/ heads your engine has? Make sure your distributor is functioning properly and timing is in the ballpark before you do anything. Ignition causes many people to spend more money than they usually have to.
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906 heads. I have not done a comp test.
Guessing my ignition system is all in check being I'm not getting any codes through my Ez efi
 
If ya "gotta have lope" then you don't want the "best cam". The best cam is the one that runs the best for your given engine. You should cam for how you want it to "run" instead. It will sound good, regardless.
 
A stock RR cam will really not have much of a lope, and should still have some decent low end? Any chance you've put a vacuum gauge on it? It may help us to tell if it's some type of aftermarket grind?

Either you have a "bigger" racy cam grind installed or you need to tune that baby a little more. Meaning I'd try bumping the initial timing as far as it will go without pinging.....Might end up in the 16/20* range, who knows, but if the engine is happy there, just make sure you modify the total timing to be not more then 36/38*. And of course, any chance of vacuum advance being involved should be blocked off for your testing at this point.
 
OldmanRick said:
A stock RR cam will really not have much of a lope, and should still have some decent low end? Any chance you've put a vacuum gauge on it? It may help us to tell if it's some type of aftermarket grind?

Either you have a "bigger" racy cam grind installed or you need to tune that baby a little more. Meaning I'd try bumping the initial timing as far as it will go without pinging.....Might end up in the 16/20* range, who knows, but if the engine is happy there, just make sure you modify the total timing to be not more then 36/38*. And of course, any chance of vacuum advance being involved should be blocked off for your testing at this point.
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you could degree the cam, it could be off . can probably change it w/o worry of problems. try changing it 4 degrees.
 
I have not done a vacuum test. The car doesn't miss a beat so I didnt figure I had any type of problem.

My guess was the engine had a Big cam in it. I was going to order a different cam today and give it a shot but maybe I should do a few tests? I like the specs on the cam posted above from Vodoo
 
schmitt said:
I have not done a vacuum test. The car doesn't miss a beat so I didnt figure I had any type of problem.

My guess was the engine had a Big cam in it. I was going to order a different cam today and give it a shot but maybe I should do a few tests? I like the specs on the cam posted above from Vodoo
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Actually,: How tall a rear diameter tire?.. Might help your final decision..?

I like a stock style type ,383 Road Runner /440 Magnum grind,here... They really work, lope doesn't necessarily mean long term relationship... You get screwed in the long term,....unless you can afford it...
 
I ran that cam a few years ago, it has you covered as far as botttom end. Im thinking the previous owned neglected or "tuned" this bad boy. My stock 68 RR 383 auto that I bought with 92,000 had no problem power braking. Usually it is something simple thats is overlooked. Especially if you dont know who installed the cam, who played with the heads, who "rebuilt the carb, etc. Start with the ignition, then the plugs wires, carb. You will track it down.
 
Abodybomber said:
Actually,: How tall a rear diameter tire?.. Might help your final decision..?

I like a stock style type ,383 Road Runner /440 Magnum grind,here... They really work, lope doesn't necessarily mean long term relationship... You get screwed in the long term,....unless you can afford it...
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I'm running 295-50-15 26.81"
 
fratzog lover said:
I ran that cam a few years ago, it has you covered as far as botttom end. Im thinking the previous owned neglected or "tuned" this bad boy. My stock 68 RR 383 auto that I bought with 92,000 had no problem power braking. Usually it is something simple thats is overlooked. Especially if you dont know who installed the cam, who played with the heads, who "rebuilt the carb, etc. Start with the ignition, then the plugs wires, carb. You will track it down.
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I'm running fast EFI so most ignition problems will set a code and I now something isn't working right. I could check the timing though, not sure if it matters for timing or not but it came from 7500 feet and is now at sea level here in WI
 
engine pic
 

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Ah, sorry I missed the ez FI Part. Carburetors are velocity-sensitive devices but cannot compensate for changes in density. Increased altitude reduces the amount of oxygen in the air, which is why carbureted cars tuned for sea level run rich when driving over the mountains at 6000 ft. when you are on vacation. Does the ez unit compensate for that? Your problem may just be a top heavy cam. MRL installs these systems, maybe he will chime in.
 
Yes the EFI adjust for Altitude automatically.
 
What should I be setting the timing too?
 
STOP! BASICS FIRST!

1)Compression test. ................... 2) leakdown test...........................3) timing tests.

Do you want to know whats wrong? Or do you want to throw parts at it until some thing, hopefully, sticks?
 
schmitt said:
What should I be setting the timing too?
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Usually 12 to 18 degrees initial and 34-38 degrees total without vacuum. With the vacuum advance if used total at cruise RPM around 45 degrees. The limiting factor on initial timing is usually hard hot start.
 
Great ^^ thank you

You guys are awesome over here
 
Ok comp test in. Sea level cold engine.

134-139
 
Yeah 140 right in the soft zone.
Too much less would put you in the dog-zone.120 is really doggy.

The way I see it is like this; You can spend money on band-aids or you can spend money on fixing the compression, or you can change the tune, or you can live with it.
--Here are the band-aids; a higher stall TC & bigger gears. Then you will need to change the governor and probably mod the VB. LOTSACASH
--Fixing the compression? New pistons and a gasket set. Or maybe some closed chamber heads.
--The tune; Ditch the cam for one about 2 or 3 sizes smaller.Forget lope, It does nothing for your vehicle. It's a by-product of cam-timing, and if not accompanied by an increase in compression, just softens the bottom-end;as you have found out.
--Live with it. really cheap, but not really an option.

A lopey cam requires a complementary increase in compression, or else it turns into your situation. RRR said it all in post#4
So now if you really are after low end and midrange, the next step is to figure out exactly what cam is in there, to see if the cam is killing your compression or if the chambers are just huge.. If you cant get the timing card or a PN then you will have to do it the hard way.You will need to degree the cam. Thats a lot of work, and really all we need to know is the intake valve closing angle, in degrees relative to a piston BDC. This is pretty simple.Do you need instruction for that?
Once that number is known, and from the cylinder pressure reading and knowing/estimating the cylinder volume, we can estimate the compression ratio, and decide what really to do.
Do you have a clue what your truck weighs?
 
Don't think that is my problem. All very close
 
What should be stock comp on 383? 150psi?
 
Yes please let me know how to get that intake valve closing messurement and I will try and get that for us.

Not sure on the weight. Not much there other then engine, trans, and Dana
 
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