Camshaft choices

[Confederate1969]

I've heard a lot of talk from friends, relatives, reading, and tv shows about cam swaps being one of the first things you do as a performance upgrade for an old engine. I've done some browsing at places online like compcams (which is based right here in Memphis) and I'm more confused now than I was before I started shopping. Seems like there are a thousand different "usage" scenarios that one can set up an engine for. I don't need to run 10s at the motorsports park or need to have enough power to raise the city smog alert 200 points doing burnouts. They ask lots of questions like "Is this a show car? Is this a drag strip king? Is this a Sunday cruiser? Do you want to reverse the Earth's rotation when you hit the gas?" and so on... Well I just want a 383 I can run rough now and then to impress friends with.

What kind of cam would you all suggest for a little more aggressive 383 than the factory intended it to be (but without having to upgrade carbs and such)? And is it typical to upgrade the valve train with the cam from the same company in order to make sure they work right together?

 

[dobie]

If I'm not mistaken, the stock original cam for the Road Runner was the stock cam from a 440. I'll be shopping for a new cam here in the next several months. I too want to go larger, but not so radical that it affects everyday driving. Numbers don't mean much to me, although I probably won't go any larger than a .509 lift cam. My plan is to call up CompCams one day and talk to them. Basically, I'm looking for something about 2-3 steps more aggressive than the stock cam. That should give me the idle and hp I'm looking for without sacrificing to much around town driving. I'd also recommend getting the whole kit, not just the camshaft. It's a good idea to replace the lifters, etc. at the same time as a new cam.

 

[dobie]

I forgot to add: Your car's options should also dictate how radical you go too. It's easier to go bigger with a 4 speed vs. auto as then you have to figure in the torque converter. Steeper gears also is a plus, along with manual brakes vs. power brakes for the vacuum issue.

 

[Hoosier Bird]

If you don't have power brakes I would go with the CompCams 292. It has a really good thump to it and makes good upper rpm horsepower. If you are going to have power brakes I would go with the CompCams 284, it will give you the vacuum that you'll need for the brakes, still has a fairly rough idle. Now I have not used it but the Competition Cams' XE 285HL is supposedly built specifically for a big block Mopar. They changed the cam lobes because the lifters are a bigger dia. than Chevy which the other two cams were based on. It's been a while but my buddy always used a purple shaft from direct connection (Mopar performance) and it was a really good all around cam too. All the cams listed above will of course require, for most effiecient performance, matched valve springs, headers, good carburetor, better intake, good ignition, etc....If you are going to leave everything stock I'd probably just put an RV cam in and be done. The first consideration is "how much junk food money do you have?". Do you have the casting #s of your heads? Don't just throw a cam in without upgrading everything that needs to be, for the cam you buy. Most cams will have special needs. Hope I didn't confuse you. :cheers:

 

[mac]

here is a thread from moparts. just more food for thought. it is about a replacement cam for big blocks and for a good stock sound and feel, to me it just makes sense.

http://board.moparts.org/ubbthreads/sho ... w=1#UNREAD

 

[Big John]

here is a thread from moparts. just more food for thought. it is about a replacement cam for big blocks and for a good stock sound and feel, to me it just makes sense.

http://board.moparts.org/ubbthreads/sho ... w=1#UNREAD

I've thought about that cam myself. I think the theory behind it is "less is more". You can't argue with the results though.

http://uk.youtube.com/watch?v=Ipb-axRrvYk

 

[Hoosier Bird]

Here is a good article.

http://www.moparmusclemagazine.com/tech ... index.html

 

[Confederate1969]

I've actually read that article several times and have it bookmarked. From what those boys say, you can evidently get a 383 performing like a hemi with a few shiny pennies. I don't want to buy a new carb. But maybe a better cam than I've got and possibly even an intake manifold upgrade could really open the old engine up.

 

[Basketcase]

now you've got me thinking about tweeking my 383. It was supposed to been rebuilt 3500 miles ago, although i can't get ahold of any former owner with any info on that. It has headers, an Edelbrock Torker w/ a Holley DP. Runs great, bt not a head snapper, but stiffer gears would probably help that. But, I don't wanna hurt the milage too much till I see where gas will be next summer.

 

[SomeCarGuy]

The stock cam in the 383HP is the 440 cam.

It is really pretty close for a car that is primarily street car. With the dizzy set up right, and a well tuned carb, it is a pretty nice cam for zero dollars. Be sure to throw a good chain in there, as I see that problem all the time. Car doesn;t run well and sure enough the factory crap chain is still in there.

 

[Plymouthfan]

Anyone know what cams were used in factory HP 4 bbl 440's? My motor is out of a 68 Charger R/T.

 

[SomeCarGuy]

same as the 383HP.

 

[mcmopar]

Specs are as follows:
advertised duration intake: 268 degrees
advertised duration exhaust: 284 degrees
overlap: 115 degrees
valve lift intake: .450"
valve lift exhaust: .455"

The new MP/DC "road runner" cam has the same advertised specs but has been redesigned with a lot more duration at .050" lift (241 degrees - same as the Hemi grind Purple Shaft) than the original. It looks to be a very healthy cam.

 

[droptop]

Specs are as follows:
advertised duration intake: 268 degrees
advertised duration exhaust: 284 degrees
overlap: 115 degrees
valve lift intake: .450"
valve lift exhaust: .455"

The new MP/DC "road runner" cam has the same advertised specs but has been redesigned with a lot more duration at .050" lift (241 degrees - same as the Hemi grind Purple Shaft) than the original. It looks to be a very healthy cam.

This is the cam that I put in my '75 Road Runner with the 400 in it. This cam, 906 heads milled 50 thou, '69 intake and exhaust manifolds, and an avs carb sure brought that car to life.

 

[toms69rr]

This is the cam that I put in my '75 Road Runner with the 400 in it. This cam, 906 heads milled 50 thou, '69 intake and exhaust manifolds, and an avs carb sure brought that car to life.

Do you have to run adjustable rockers with that cam?

 

[mcmopar]

Nope - its a hydraulic so the stock rockers and pushrods will work just fine.

 

[droptop]

This is the cam that I put in my '75 Road Runner with the 400 in it. This cam, 906 heads milled 50 thou, '69 intake and exhaust manifolds, and an avs carb sure brought that car to life.

Do you have to run adjustable rockers with that cam?

No.

 

[toms69rr]

I have been waiting since early September for a set of Comp cam adjustable rockers for my Comp Cam, Been on back order with them.
I thinking of going with some thing different,and using my new stock rockers and shafts.
Any suggestions?
383 Bored .040
Keith black pistons
Decked .020 (clean up)
Eagle H-Beam rods
Stock Forge Crank ( just needed polishing)
906 Heads mild porting then polished .006 (clean-up)
Comp Cams XE 268H.
Double roller chain and gear
Edelbrock 750
running stock HP Manifolds
2.5 exhaust with H pipe
4 Speed
8 3/4 sure grip 489 case 3:55 gear
This is a numbers matching car, so I did not go wild on the build.
Not a race car, Just want a good street able car with a good sound.
Thanks Tom

 

[mcmopar]

That's a very nice combination and should run extremely well. You don't need the adjustable rockers so I'd stick with the stock rockers for ease of maintenance (which is zero) and save some $$$. On the heads - make sure to have hardened exhaust valve seats installed for running today's unleaded fuel. Or if you don't install the hardened seats get some Max Lead 2000 and run about 200ml per tankful of gas. This is real teraethyl lead that was used in the good old days. It protects the valve seats and gives a bit more octane. I've seen the effects of unleaded fuel on Mopar heads that did not have the hardened valve seats and it is not pretty. one valve was sunk nearly .020" into the head which is not a good thing! I use it in my 10.5:1 engine (compression is possibly higher) at the above described dosage and I don't get any ping under acceleration even with regular fuel. The stuff isn't cheap ($45/gallon last time I checked: 4-1 qt bottles) but at 200 ml per tank it will last well over a year if you only drive 3000 miles a year. You can buy 2 bottles instead of 4 if you want to keep costs down and still drive a very long time before you use it all up.

I don't know what you have planned for mufflers but if I may offer a suggestion or two I think I'd consider the Dynomax Hemi Super Turbo or Ultraflow mufflers or the Magnaflow mufflers. The Dynomax Ultraflow and Magnaflow mufflers use a very similar (almost identical) straight through design which is very efficient but a bit louder than the Super Turbos. I have spoken with more than a few friends who have Flowmasters on their cars and they don't like them because at certain RPM's they tend to reverberate very loudly. One buddy of mine even wore ear plugs when driving his car because it was so bad.
I went with the Magnaflows because in all the comparison reviews I saw they outflowed the Flowmasters by quite a large margin and were still a bit quieter. The Hemi Super Turbos don't flow quite so well but are quieter which is a big plus on a road trip. If you want a good street sound along with acceptable freeway noise and great flow charactersitics the Magnaflow or Ultraflow mufflers would be your best bet.

BTW what intake are you using? An Edelbrock Performer or Mopar Performance M1 dual plane would be perfect for your setup, would look stock if painted and would shave at least 20 pounds off the front end of the car.

 

[toms69rr]

I do have harden seats on the heads, The motor is built. I used the stock intake, again it not going to be a racer, just a driver with a little A$$.
Machine shop put the short block together,and put in the XE 268H in her.
After sitting on the stand for about six months. had to finish body work and paint (One man crew, me) I put the motor and tranny in. Got her running. Ran pretty well.
Car would set for a couple weeks at a time while I work on interior Dash etc.
I would start her back up and she would run like pooh pooh, come to find out the plugs would be fouled,So I would change plugs mess with carb,It would run good for that day,Set two weeks it would do it again,
Well after playing with timing and changing carbs a couple times,it would set for couple weeks and do the same thing.
So being a little miffed by this point,I pulled the cam out and did some measuring and found out my valves were not closing all the way (Stock Rockers and Shafts) need adjustable. should of checked, But left it up to machine shop to put the right cam back in or a least tell me it needed adjustable.
I order Adjustable Rockers from Comp Cams on Sept 10-08 I just called again this Morning and they still are on back order.
and they make the stuff.
So that is why I am asking which cam to run?
At this point I rather just replace the cam and use what I have (Cheaper) and may be just as good

Again Thanks Tom