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Looking for a cam

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by possum, Jan 23, 2003.

  1. possum

    possum Registered Member

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    I have a 78 /forums/images/graemlins/k5.gif. 350, blah, blah, blah. I'm unimpressed with my engine and will be rebuilding another one to swap in. I want a low end torque camshaft. I don't know what numbers to look for but found one in a catalog that lists a 600-1100 rpm power range. Is that too low? I really don't like giving a lot of gas just to get up a small hill or pull something heavy. I'm not real interested in horsepower as I don't drive it at higher speeds for long distances but I would like being able to get "off the line" quicker. \
    I'm trying to rebuild a 350 the way I want it and do it right the first time. Any suggestions are appreciated.

    and what carburetor would work well?

    possum /forums/images/graemlins/1zhelp.gif
     
  2. BorregoK5

    BorregoK5 1/2 ton status

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    Take a look at the Comp Cams 12-231-2 grind at teh top of this list:

    http://www.compcams.com/catalog/078_079.html

    It has loads of bottom end and breathes well at higher rpm. I've run a lot of scenarios against this cam in various dyno software and I'm really pleased with the results. I run this cam in my 415ci stroker small block as well and I'm very pleased with the overall performance. For each step from this cam you gain peak hp/tq numbers but loose hp/tq at equal low rpm. Open up the breathing on this cam and you loose a little on the bottom end (almost negligable) and gain quite a bit more top end. Good for grunt pulling, rock crawling and fuel economy. As for a carb, you'll find the stock Q-Jet will do great off road, the smaller primaries will do good for off the line performance and give you great gas mileage on road.
     
  3. heavy4x4

    heavy4x4 1/2 ton status

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    My first suggestion is to call a cam manufacturer and tell them exactly what you're looking for.
    Being that you don't have a computer controlled engine, you could go pretty radical if you want. But I wouldn't. Maybe look at the Comp Cams 4x4 line. They make great low-end torque, and also work well to provide good engine vacuum.
    As far as the range to look for...go for something listed in the idle-5500rpm range. Not 1500-6000rpm range. I have never seen a cam listed with such a specific, and low, range as the one you said...but even at that, it sounds a little too low to me.

    About the carb...I'll let someone else handle that question - I'm not much of a carb guy.
     
  4. Sidepipes

    Sidepipes 1/2 ton status

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    You'll need to supply some that Blah, Blah Blah . Like compression ratio, what intake you have and what carb you are running.

    600-1100 seems a little to tight of a power band for a gas engine. Usually they'll state idle to 3500 or something like that.

    If you are running a stock steel intake, put some extra money together and get an aluminum intake( something like a performer) they flow much better than a stock steel one. You have to remove the intake anyways so why not replace it. A quadrajet should work fine..... probably better than any other carb if you want a mild engine. The small primaries promote high intake velocity which is what you want in this application.

    Get some more spec on the cam you want and we can check it out.
     
  5. tarussell

    tarussell 1/2 ton status

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    Look for a cam that is very conservative on the durration @.050 and the most lift that the lobe will allow. You want as much cylinder pressure as possible, down low , for good bottom end power.
    I'll put in another vote for the Q-jet , the small primary's are great for slow going and good throttle response.
    Tom
     
  6. Z3PR

    Z3PR Banned

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    Sounds to me like you need lower gears. What axles are you running with what gears with what size of tires ????
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Vortec heads. You'll see more power gain out of Vortec heads (and the matching intake) than you will with a better camshaft and crappy older heads.

    It's more expensive than a cam swap, but you are wasting your time on a camshaft that holds the valves open longer or further, if the heads and exhaust can't ingest and expel the mixture and leftovers. Vortecs are made for down low power (thus the truck only application of them) and for the price, can't be beat, especially since it sounds like you want low end power, not some high RPM mud pit runner. (in which case the Vortecs wouldn't be the ticket)

    And if you haven't already, go with headers. Thats another easy 15+ HP for almost any V8 out there over manifolds.

    Thats my two cents.
     
  8. possum

    possum Registered Member

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    I don't know the compression or any technical stuff like that. I'm fairly new to all this. I bought what I was told was OEM replacement QuadraJet from Edelbrock. They said Rochester no longer made the carb and Edelbrock now manufactured the line. It's 650 cfm and everyone is telling me it is too big and I should have gone with 600 cfm. I agree now but Edelbrock told me 650 is what I had originally. Oh well.
    I have 33s on the 12bolt/Dana 44 combo with standard 3.08s for now. But I'm always looking for the 14b/Dana 60. /forums/images/graemlins/grin.gif I know I need lower gears. It's just easier to convince the missus for a "proper" engine than 1 ton axels. They will come later.
    Other blah, blah, blah ar TH350 tranny and NP203 transfer case... 4"lift.

    possum
     
  9. BorregoK5

    BorregoK5 1/2 ton status

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    Building in torque is less expensive than you'd think. Here is what I would suggest if you’re on a budget. Put the majority of your cash into the bottom ends since changes to this area down the road require pulling the engine, but heads / intake / exhaust etc can be done with the engine in the truck. Take your raw block in and have it checked / prepped (magnafluxed, heat treated, shot peened, true’d etc..) For what your after, a cast rotating assembly will be more than enough, going with a forged assembly adds rotational weight which wont perform as well at lower rpms. A good set of Hypereutectic pistons would be cost effective and perform well. Target your compression ratio for about 9:1 with these pistons but no higher. Take into account that if you plan to swap on different heads down the line, that your target compression ratio reflects the chamber size of those heads, and not the ones you may be using in the meantime (Vortecs have a 64cc chamber , your stockers are probably 76cc’s). Running a set of aluminum heads may allow you to push a higher compression ratio, but they are not as kind to high heat, should that condition arise. Invest in a good double roller timing chain, more for longevity than performance. If you decide to run a high volume oil pump, you would be good to look into an extra capacity oil pan as well… too often people suck up all the oil and waste bearings. With a towing cam, you can run stock lifters, valve springs, pushrods etc so parts are real inexpensive. A good dual plane aluminum manifold is a good idea, as are headers. Your 650 Edelbrock is fine as well.
     
  10. bajaviking

    bajaviking 1/2 ton status

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    I have exactly the same gears and tire size as you and I just spend about $500 on getting a crower cam, double roller timing chain, dual exhaust and Edelbrock Performer Intake and I am now convinced that I should have spent the money on 4.10 gears instead. The engine runs good and it revs up much better but what I really wanted was low end grunt. If you want more accelaration I would go with gears.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Edelbrock only makes 750, 800 and 850CFM Q-jets, and OEM was only 750 or 800, so "everyone" (including Edelbrock apparently) is wrong. It's not oversized for your engine, don't listen to them. May need some fine tuning (scratch that, WILL) if you haven't already to get the best performance and mileage.

    Unless you put something in there with tons more torque (like a 454) I think you'll be disappointed with your combo. Those gears and those tires are INCREDIBLY mismatched, and are really holding you back. A cam, intake, heads, etc. can't fix a 350 trying to turn 3.08's with 33" tires.

    Invest the money in gears or the 1 ton setup, you'll probably be able to tolerate the "weak" engine longer with different gears.
     
  12. sdavid

    sdavid 1/2 ton status

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    You would be surprised what a set of axles with 3.73 gears would make. You can stay 1/2 ton and probably get a matched set for little to nothing. Check out the Parts for Sale forum. They are falling out of the sky over there. /forums/images/graemlins/wink.gif
     
  13. Z3PR

    Z3PR Banned

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    Depending on how large of tires you plan on running, you could just get the 3/4 Ton axles. I got mine for only $250.00 for both. It gets ya the lower gears and in my opinnion, it's cheaper then doing the gear swap and hella stronger then staying 1/2 ton (Note: 3/4 ton front axle not stronger then 1/2 ton version, but nowhere the $$$ of a Dana 60) !!!!!!!
     
  14. Sidepipes

    Sidepipes 1/2 ton status

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    Dorian is right on this factory qjets were 750 or 795 cfm. You must be thinking of the edelbrock performer AFB's they come in 600-650-750-800.

    They have a cool new one out with an adjustable secondary air valve, which to me was the biggest let down of the carter/edelbrock AFB's.
     
  15. wrathORC

    wrathORC 1/2 ton status

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    I've got 2.73s and 33s. I can light up the tires like there's no tomorrow and paint the asphalt red with 5.4L-equipped F150s. However, for the life of me I can't hold 70mph on the expressway in overdrive. Heck, 60mph is a chore. It's gutless even in 3rd gear. In fact, when third gear rolls around at 65-70mph under WOT it practically falls flat on its face.

    I'd invest in gears or new axles before you do any motor work. I tried getting more ponies out of the motor instead of going the axle route. I learned my lesson. If you have a TH350 without the locking torque converter (chances are yours doesn't lock) I'd aim for 3.73s if you plan on keeping the 33s.
     

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