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  1. #1

    Default 350tbi breathing problem

    94 chevy with 5.7 tbi put a chip on it which helped, then i played with the intake, took all the snorkel stuff off leaving just the air filter pan sitting on top of the throttle body with a k&n filter thinking it would free up some flow, it helped, but then, i put on a k&n cold air intake and im not sure if its any better, shouldnt this like REALLY help, high rpm power is ok but man did i loose the bottom end, anyone ever had this happen, is my 350tbi made to run better with a little air restriction??? what should i do???? would a throttle body spacer help???? oh and im running 4:10s

  2. #2


    The 350 L05 engine was never made for high-RPM horsepower. It's a pickup truck engine, through and through. I'd say definitely use a K&N filter for the better crap-catching, but the stock air box will actually give you a lot better performance than the cold-air intake. I tried the cold-air thing once and ended up backfiring.

  3. #3


    awsome thanks man, yeah ill change it tomorrow, during my baby shower lol where should i go from here??? im looking for more hp, i have some headers im going to put on, but what else can waken up this motor? it has a hypertech chip right now, and no i cant afford a blower lol

  4. #4


    A good set of headers will help matters along, but keep a bit of backpressure in the exhaust. Too little backpressure will actually cut down the low-end torque.
    Next thing I would do is get a mild camshaft. Give me a couple of minutes here, and I'll add a link to this post.
    This is the perfect cam for the L05's power band.
    Last edited by Chris Miller; 03-13-2009 at 11:49 PM.

  5. #5


    sweet now were talkin, ok ive never put one in, what all is this gonna take? obviously engine extract but once in then what? timing? computer work? i dont want to end up paying a bunch more to make my motor run with it know what i mean

  6. #6


    The downside to changing the camshaft is that you will have to take off you water pump, harmonic balancer, basically the front of the motor. But, if you pop the radiator out and move the condenser over, you can do it without taking the motor out. This cam, being mild as it is, won't require spectacular timing changes, maybe a degree or two.
    Grab yourself a Haynes manual and read the heck out of Chapter 2.
    Changing the lifters and pushrods will obviously require that you take the valve covers and intake off, but on that engine, it's really not hard at all, just a bit time-consuming. Once you've got it apart, putting the cam in is easy; just point the mark on the crank straight up and the dowel pin on the cam 90 degrees to the left, then pop your chain on.

  7. #7


    cool, yeah i just had the grill off to paint it so i could just take it off then the radiator and move the condensor, i think i seen them timing lights at napa or something, now you said this cam is mild, is it worth the money???? i LOVE the way a motor with a bad ass cam sounds at idle, i know this is no ss chevelle but am i really gonna feel and hear a difference, i have a month old baby, i want my money to go to things that really work lol

  8. #8
    TrailLeadr's Avatar
    Join Date
    Jun 2005
    Coventry, Rhode Island


    Since you're going to be in there removing rockers to get at the pushrods and lifters, you could also replace them with roller rockers. They can be a little pricey depending on what you buy, but they're a quick easy hp gain.
    Rhode Island

  9. #9
    dwill3015's Avatar
    Join Date
    Jan 2007
    Yacolt, Washington
    Blog Entries


    On my 87 Blazer ( same TBI 350) i chipped it, installed a TB spacer, and turned the lid upside down on my factory aircleaner and it made a big difference.
    Washington State
    2006 Silverado 2500HD LT3 4X4 CC SB Duramax LBZ
    Tuff Country 6" lift, 35" Toyo M/T's on 20" Ultra Peacemaker wheels, Quadzilla Stealth2 programmer, Diamond Eye 5" cat-back exhaust, factory Special order color Yellow.

  10. #10


    Yeah, that was one of the last years they used a good cam in the L05. Most of the later TBI cams, 89 and later, I think, seem to wear out a lot faster. The cam I posted won't push the engine up into the 400+ hp range, but it will give a healthy jump in horsepower and bottom-end torque, which will really help get the truck moving.
    As for rockers, yes, roller rockers are a good way to go. A quick and easy way to get a little extra power is to get a little bit higher rocker ratio and new valve springs(just a little stiffer than stock, but not that much more).
    If you want something with a heavier idle and more top-end power, you'll have to upgrade the heads, and probably the crankshaft as well. High-performance heads and crank will probably put you into the $1500-2000 price range, though.

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