383 runs like a giant turd WTF

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Was the block decked? Were the heads CC'ed? You can't assume that the compression is 10:1 or whatever unless you actually measure everything and do the calculations.

As far as the cam, I know there are a lot of Purple Shaft fans on here, but they leave a lot to be desired, in my opinion.

Ditch the cam, put in a Lunati VooDoo grind and swap the intake for a Performer RPM dual plane.
 
Put in a 4.30+ gear and let out of the clutch at 3k. The engine combo might find zen there.
 
YoungBlood said:
Put in a 4.30+ gear and let out of the clutch at 3k. The engine combo might find zen there.
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Just a terrible combo, ive ran it pretty high it just doesnt run.


What do you guys think would be a good cam i wasnt the lumpy sound and what intake


The thing that has me confused is we have a magnum 360 stock 8:7:1 comp with 292 509/513 cam MP m1 intake in a panther pink 67 a-100 it runs 12.70s its an even smaller engine less compression yet the same cam "almost" yet it runs like a raped ape with little more then $1000 in the entire build
 
roadrunnerh said:
More info is needed. Who built this motor? Did they know what they were doing? what is the compression ratio? Was the block machined properly?
A 509 cam and 750 DP is not 1970 "stock specs".
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I think most people will agree those are not stock specs i should have worded it better for those of you who have to nit pick to show there intelligence.
 
My setup runs 7.50s 1/8 miles all day on street tires and factory exhaust system and premium. The cam needs to be advanced. I would not go +8 but +4 is safe. You did not say if it is an HP, if so then check your valve clearance after advancing it. Mine is fine on the intake but exhaust valves are tight. That said make sure the valve springs are good and installed to the correct height. With the 4 speed And gear combo you have I would bet it pulls all the way to 7200-7500 or higher. My set-up works best to around 6000 on the shifts with the automatic and 4.56 gears. Like you, i was very dissapointed after installing this cam. A little extra work to go back in and add the advance bushing but it was worth it. I am glad I did not switch back the the 284/484.
 
Put the cam in at 102 or better yet, 100 if you have valve clearance.

Plenty of initial timing, 20ish+, and make sure the rest comes in FAST. More gear would help if the tire is tall, 28 inches or taller.
 
MP suggests the 110 cam goes in at 108 IIRC. Getting down to 102 is a lot and will cause worse idle problems. NO?
 
Hemirunner said:
Throw that cam away... it's way too much cam for that engine. You need something in the [email protected] range and it'll sing. That combo would be lucky if its got 8.5:1 CR.
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I'm betting this guess on compression is pretty close,and that is a lot of cam for a 383. It could be made to work, but I think it is too much to provide any real bottom end power.

I have -.020" in the hole flat tops, (no valve reliefs), milled closed chamber heads with bigger valves, (eats up CC's) and don't crack 10/1 compression with a .039" head gasket.
 
I would check your ignition curve before swapping cams. Theres a ton of power and better driveablity to be had in a properly set distributor,
 
Hemirunner said:
Throw that cam away... it's way too much cam for that engine. You need something in the [email protected] range and it'll sing. That combo would be lucky if its got 8.5:1 CR.
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I like the cam idea with the regards to the rest of the drive train and possible low ratio. I remember what you said, but just be sure of the exact ratio. If it is a mistake and it is low, a cam change would be a huge plus.

AdamR said:
I would check your ignition curve before swapping cams. Theres a ton of power and better driveablity to be had in a properly set distributor,
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Agreed. Re check the simple things first before possibly throwing dollars at a sense issue.
Check check check and then re-check check check.

No one is immune from mistakes no matter how long they have been at it. From new guy to a old fossil, crap happens.
 
383's are hard to build compression with .

How about answering the questions that Jim Lusk asked ? The available pistons for a 383 suck so getting compression is hard to do without a lot of machining after number crunching.

a friend had a 383 with trw dome pistons , a crane 300 cam and a torquer intake with stock manifolds , it was a total pig .

Maybe I impress easy but my totally stock 69 383 HP in my Dart with a 4 speed and 3.91's has done 99.5 in the 1/4 with the cam retarded maybe 10 degrees because of an increadibly loose timing chain.
 
Someone here replied previously with that same thought process...the only forged slugs I know of that would be worth a damn for a 383 would be the Diamond flat tops...nice close to zero deck pistons with healthy reliefs big enough for 2.14/1.81 valves...but you still need small chamber heads...

Downside? They're $600...unless you guys know of some more forgings available elsewhere...seems like there are tons available for 383 strokers and for 400s, and 440s...but nothing nice for a regular old 383
 
crackedback said:
Why would it cause a worse idle?
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Yea, i think as long as the mechanical's are not in play, the idle quality and drivability would still be good. Now, top end power would surely suffer some imo. But if low end is a priority........
 
crackedback said:
Why would it cause a worse idle?
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It is what I have Experianced in the past.
But, LOL
Hell, I'm asking you. I think I asked this before.
It is listed as on a 110 and recommended to be moved to a 108. (2*)
You move it to 102, a total of 8*

The cam I exp. it with was a circle track cam. This very well may have had something to do with it.
 
cracked, rumble......I think i actully agree with both of you....lol. I've never moved a cam that far and if that what it takes, another grind is probably the best answer.
 
I agree !!!

But you'll find cracked always saying to move a cam that far.
 
Yea. He does. I have never advanced a cam that far so I can not speak about it much. I had a circle track cam ground on a 108 and installed it @'106 as per instructions. Tried it both ways and 2 more for fun.

Good night
 
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