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Discussion Starter #1
I am in the process of installing a 350 engine (#14010207) into my 1983 c30 3+3 dually. I want to slam a cam in first. What cam would be best for towing?? I was looking at a summit, and they have several options available. The engine is stock as far as I know. How do you calculate the lift and duration needed for best performance???? Does anyone know what the stock L&D numbers are for that engine??

:cool:
 

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GM crate motor? I think there are a few things you need to know before selecting a cam. Gears, trans, valve sizes, intake, carb size and intended use.
 

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I wouldnt void the warranty on a new GM crate engine......if thats what it is.
 

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I've used the Comp Cam 268 in a couple vehicles with good results. It's a nice RV type cam with low grunt yet ample breathing up to about 4500 rpm. It's mid range curve is real nice, and that's where most of your work will be done.
 

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Discussion Starter #6
Cam

It's not a new crate engine, It's just a good runninng 4-bolt. Early '80's model. I know how these things wear on the CAM, so I thought I would put in new cam, and timing set when it was out. I have a c30, 3+3, so the gearing is low. maybe 4.11 and it has a turbo 400 (for now, nv4500 someday). This engine also has the edelbrock preformer intake and something like a 500 or 600 carb, but I will eventually put on a 2bbl because I like them best in a truck. I save my 4bbl's for the cars.

I'm looking for a good cam for towing. Nothing too elaborate, just a litter more umphhh
 

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Edelbrock

I see two styles by Edelbrock offered at summit. There is a "rpm", and a "plus". I am assuming the preformer plus is the one.

There are two "preformer plus" cams offered.

One has lift/dur at 278/288
other one lift/dur at 244/264

I am assuming the first one??????

My friend put a 282/292 summit in his 305, the thing ran like a raped ape.

What difference would it be in a 350 instead of a 305??

Thanks guys!!!??!!:D
 

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Discussion Starter #10
hmmmmmmmm

I just talked to the local machine shop and they recommend something a little bit less.(than 282/292)

so I went back to summit, and did a search on "towing" and all the ones for towing came back with less duration. (than 282/292)

I am not sure which rpm range would be best for towing. the 262/272 duration is from idle to 5500 rpm.

The local machine shop came back with a 270/278 dur, lifters, timing set, gaskets for $170.

:grinz
 

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Don't go nuts on the cam.

In a big heavy crew cab dually,your going to need lots of low RPM torque to get it moving.Even the performer cams may be too much,as they are still meant to make high RPM horsepower.

A true low duration RV cam would be your best bet.

Without compression ratio,carb and manifold selection,trans and gear ratios,it's tough to give you a recommedation.

Make sure your not running big heads either.Stock small valve heads will make more torque.Some mild porting and gasket matching wil help.

Your biggest gains are going to be in timing curves and carb tuning.A quadrajet is the way to go,on a Z28 or stock 4BBL manifold.

Proper exhaust selection and pipe sizes are crucial to making it all work down low.
 

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The Performer cam is matched to the Performer manifold and is touted as an R/V cam. It would be a good selection for what you want to do. The Performer RPM should be ruled out. I think the 270/278 cam you've listed is still a bit stout, when I did my research in building my engines, the 268 Comp Cam was at about the upper limit of where I wanted to be. I advanced the cam timing 2° to bring the curve in a bit quicker. I ran this setup on both a Mustang I had and my '81 F-350 plow truck. Both worked well in the rpm ranges I ran, maxing out at about 4500rpm. It idles with just a hint of frump, yet comes off idle quickly with no stumble. It would be a good selection if you want just a bit of edge over the Performer package.
 

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whiteys said:
How bad will this affect my gas mileage???

:eek:
Under the right circumstances, you may even see an increase! Depends on how badly the engine struggled up to speed the way it was, or how worn out the old cam was.

In my truck I see a definate increase in fuel mileage swapping in bigger cubes, simply because the engine doesn't lug so much trying to pull the truck around.
 

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Derek is right.If you do it right,you will increase the volumetric efficiency of the engine,and increase fuel economy.Maximizing power at your normal cruising RPM is also important.

A good rule of thumb with cams,is do you research,match the cam to the engine,and then pick the next smaller cam.Most cam mfgs are a little aggresive with their recommendations.

You can also get a little more power with some good roller rocker arms.If you keep the cam on the conservative side,you can use a higher ratio rocker to gain some more lift without affecting duration too much.

Degree the cam in,and use a good roller timing chain,so the cam timing will stay where you put it.

Call Lunati.They have some of the best cam techs out there,who are honest when recommending cams.
 

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Discussion Starter #16
Cam In

THE CAM IS IN, ALONG WITH DOUBLE ROLLER TIMING CHAIN. I ENDED UP WITH A MELLING#22109 DURATION AT 270/278

HOPEFULLY MAKE THIS STOCK 350 (14010207) RUMBLE!!

:grinz
 

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Discussion Starter #17
heads

Make sure your not running big heads either.Stock small valve heads will make more torque.Some mild porting and gasket matching wil help.
My heads on this engine say 462624
Is this a smaller head?


I have a high compression goodwrench in my other truck and i was told this meant it had 305 heads on it. Is this true??



Would I be better to change my heads to balance out the cam???

I'm also putting on headers and cherry bombs with big diameter pipes out behind the tires.




great link: CAM Basics
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http://www.chevyhiperformance.com/techarticles/148_0505_camshaft_basics/index.html

:cool:
 

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Discussion Starter #19
305 head

THANKS FOR ALL THE HELP GUYS!!!:huh


What head would best suit my needs. (Lots of low end torque) for a 1-ton, 3+3 cab Dually. I got the 270/278 duration cam.

Will 305 heads work? Or would a 350 head be better????

It seams that 305 heads would help mileage, but will they really help low end power matched to the cam?

:grinz
 

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whiteys said:
THANKS FOR ALL THE HELP GUYS!!!:huh


What head would best suit my needs. (Lots of low end torque) for a 1-ton, 3+3 cab Dually. I got the 270/278 duration cam.

Will 305 heads work? Or would a 350 head be better????

It seams that 305 heads would help mileage, but will they really help low end power matched to the cam?

:grinz
The 305HO heads (casting 416)would bump your compression up to around 10:1, ie: premium fuel ALL the time, especially in such a heavy vehicle. They work excellent with cams around that size, and the slightly smaller 1.84" intake valves and ports create more velocity than flow.... torque and vaccuum! You could probably do it with a thick composite head gasket but I wouldn't be surprised if you needed the premium fuel. I love these heads for street performance motors... just no experience with them in truck use.

If you could afford it, the Vortec heads and Performer Vortec intake would be a beautiful combination...
 
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