Picking a cam/rebuild advice for 350 in 84 c1500

Discussion in 'Engine & Performance' started by bman1985, Nov 14, 2017.

  1. bman1985

    bman1985 Junior Member

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    My 84 c1500's motor is starting to smoke under load and my th350 lost 3rd gear so it looks like this winter I'll be rebuilding my power train. The truck currently has a carbed goodwrench 350 from the junk yard that the previous owner put in some time before I bought the truck. I replaced the quadrajet with a performer rpm intake and summit 600cfm carb it also has headers.

    I'm looking to get some more power when I rebuild to make this thing more fun to drive. I don't want to spend a ton though so ls swap is not an option. I do use the truck for truck stuff like running to home depot, the dump and towing my boat so I do need some low end torque but I'd like to be able to burn up the red lights when it's empty.

    Here's my thoughts for the rebuild:
    Bore as needed
    Replace dish with new flat top pistons
    Replace stock heads with vortec heads
    Install a new cam-need help picking which one!
    Rebuild th350 trans, replace torque converter with appropriate stall for the cam

    I really have no idea what gear ratio is in the rear.

    I want to keep the 600cfm carb for cost reasons but I know I'll need a new intake manifold for the vortec heads.
     
  2. 75gmck25

    75gmck25 Full Access Member

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    I would expect an '84 to have had a 700R4 transmission, not a TH350. If you can buy a decent 700R4, that would be better than rebuilding the TH350, since you could run much lower rear end ratio and still have good RPM on the highway.

    Considering all the work you want to do to your block, I would also look around for a low mileage Vortec 350 from a 96+ truck, and just swap engines. You will get the roller cam setup and Vortec heads all in one package. Then just swap in a hotter cam and switch to a carburetor. Modern fuel injected engines wear out slowly because the computer keeps everything within very tight parameters. A engine with 110-120k miles often still has 100k miles left before needing significant work.

    Your engine build is very typical, and should work well to get in the range of about 350 hp (or more) with the right cam. Due to the weight of your truck, you probably don't want cam duration to be more than about 218-220 @ .050, but with a high stall converter you might go a little higher duration. If you do a retro-fit roller cam (quite a bit more expensive for the kit), you can use a relatively aggressive cam that ramps up quickly, and still not worry about wiping a lobe.

    Make sure you get the Vortec heads modified to allow for cam lift more than .475, because it will give you a lot more choices. Having them tapped for screw in studs (vs. press in) is also a good idea when you use a stronger springs. There is usually no point in using a cam with more than about .510 lift with Vortec heads because they are optimized for low and mid range torque. Vortecs are excellent because they have strong low and mid range, but they do eventually drop off.

    If you keep your TH350, you could swap in a 3/4 ton rear end and its usually easy to find 4.10 gears. With stock height tires (about 31") you will definitely get away from a red light quickly. 'However, if you swap to a 700R4 instead, you will get a lower 1st gear (3.06 vs. 2.52) and a .70 overdrive. Its the best of both for a 2WD truck.


    Bruce
     
    Last edited: Nov 14, 2017
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  3. 4WDKC

    4WDKC Full Access Member

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    Quick budget calculator

    Bore as needed ?
    Replace dish with new flat top pistons & rings $249
    Replace stock heads with vortec heads $500+
    Install a new cam-need help picking which one! Flat tappet with lifters $150 or, retro roller $600+

    How much can you get a LS for in your area?
     
  4. Honky Kong jr

    Honky Kong jr Super Sarcastic Man

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    Big block....
     
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  5. shiftpro

    shiftpro Full Access Member

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    Another consideration would be stroking a sb. Make it a 383...
     
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  6. OkieFishMan

    OkieFishMan Certified Camping and Fishing Nut

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    Well said sir!!!!!!

    OP: My truck isn't fast enough, what do I do?
    Honky: BIG BLOCK!!!

    OP: My truck needs more towing power, what do I do?
    Honky: BIG BLOCK!!!

    OP: My truck has terrible brakes, what should I do?
    Honky: BIG BLOCK!!!

    I see a pattern @Honky Kong jr , but I like it!!!!!!! lol:happy175::happy175::happy175:
     
  7. Honky Kong jr

    Honky Kong jr Super Sarcastic Man

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    Well for better brakes big block and hydraboost
     
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  8. RustyPile

    RustyPile Full Access Member

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    There is no substitution for cubic inches...:favorites37:
     
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  9. bman1985

    bman1985 Junior Member

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    A 383 or big block would be sweet but to much money.

    @75gmck25 good suggestion to find a 96+ vortec motor. That probably is less work with similar cost. I heard a lot of bad things about 700r4 transmissions, are they reliable with a higher output motor?

    I went to the junk yard today, a 5.3 ls is about the same as the vortec motor but the ls will cost way more to install. I don't think I can justify the extra cost. I also don't like the look of all the plastic on an ls motor in a classic truck.
     
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  10. Rusty Nail

    Rusty Nail Deo Vindice

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    Except NOS.

    Why didn't budget guy up there mention you can bolt on 125 horsepower at the touch of a button for $400?

    No need for any of that other stuff...:grd:

    http://www.jegs.com/i/NOS/741/05000/10002/-1
     
    Last edited: Nov 14, 2017
  11. OkieFishMan

    OkieFishMan Certified Camping and Fishing Nut

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    Ditch all the electronics and throw a carb on it. Still be a damn good motor.
     
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  12. OkieFishMan

    OkieFishMan Certified Camping and Fishing Nut

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    As for the 700r4, yes in stock form they are a bit weak. You can have them built to handle a fairly hot small block for reasonable. A decade ago I had an '87 K5 with a warmed over small block, prob 350 to 375 horse. I had the awesome tranny shop here work it over and it was awesome. Drove it probably 30k miles before I sold it (stupid decision) and never had a lick of trouble. The bad part was that even back then it was $1,000 to have that done. Nowadays I bet you're looking close to $1,500. Just guessing.
     
  13. Honky Kong jr

    Honky Kong jr Super Sarcastic Man

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    Well my engine isn’t big on inches but it makes up for it in attitude and the right combination of parts.....for now....I hope lol
     
  14. shiftpro

    shiftpro Full Access Member

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    The 700 is one of the more pricey rebuilds, if you do it right and make it stronger. Even a stock rebuild is $$$.
     
  15. shiftpro

    shiftpro Full Access Member

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    Depends... if you need to grind your crank, resize your rods, but new pistons... a kit won't be much more than all that. And if you shop, hard, and smart, you can find guys and shops even liquidating parts for these old mills all the time. Guy buy parts and they sit for years and eventually go for sale cheap...
    It's nice to have the $ to buy shit when you see it, even though you don't need it!
     

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