Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Swapping in 350 SBC -- removing EGR and other smog crap

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by tungsten, Jan 28, 2004.

  1. tungsten

    tungsten 1/2 ton status

    Joined:
    Oct 29, 2003
    Posts:
    104
    Likes Received:
    0
    Location:
    Nashville, TN
    Okay, the various answers to my questions may appear in other posts but I've done some searching and only ended up crosseyed and with a headache trying to sort it all out. So please forgive me if I am asking something that has, in one way or another, been answered before. /forums/images/graemlins/grin.gif


    I am preparing to pull the 305 SBC engine out of my 1985 K5 Blazer and will replace it with a 350 GM crate engine. The 305 obviously has the A.I.R. system and other smog crap all over it. I want to get rid of that stuff, retain the catalytic converter for emissions testing reasons, and basically reduce the clutter in my engine bay.

    I have an Edelbrock Performer RPM dual-plane non-EGR intake. I will be buying an Edelbrock #1406 Performer non-EGR carburetor with electric choke.

    I will most likely be replacing the factory exhaust manifolds with something that does not have all of the AIR plumbing hanging off of them. I am open to suggestions as to which headers to use. Prefer shorties so that I don't have to do any custom exhaust fabrication, but can resign myself to using long tubes. /forums/images/graemlins/wink.gif

    My questions are simple:

    If I do all of this, can I chuck the big air cleaner assembly with the heat riser and other extraneous garbage and just run a simple open element air cleaner?

    I presume that there is at least one smog pump on the 305 somewhere. I admit that I haven't done much crawling around in the engine bay yet because the temperatures outside have been in the teens or single digits and I haven't been able to muster up the willpower to go do it.

    Is there just one smog pump or more than one on the 305? If I chuck these, I presume that I must use shorter V-Belts ... correct?

    Finally, it's my understanding that there isn't an ECM computer on these 1985 rigs, so I won't have to worry about all of these changes mucking up a computer or anything like that. I rather doubt it even has 02 sensors, but I may be wrong. Am I right on both of these points?

    Thanks. Just trying to do some homework and eliminate any surprises when I get ready to tear into this engine swap.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    First, off, some of your ideas are not well planned out. A 305 EGR carb is going to run LEAN at cruise without EGR. You will more than likely need to re-jet the carb. Every time I've put an EGR carb on a non-EGR motor I had to.

    Second, there is nothing wrong with the factory snorkel filter in almost all applications. Cold air makes more power than warm air.

    Getting rid of the "extraneous garbage" isn't always a good thing. If you are worried about passing a sniffer, you had better make sure that thing is running right after removing EGR, because if it's running lean and/or the converter is "worn out", you'll fail.

    Unless thats a CA rig, then you won't have an ECM, although with that being a 305, I'm betting you have ESC. If you don't know this, you really should question whether or not you know what you are getting into.
     
  3. tungsten

    tungsten 1/2 ton status

    Joined:
    Oct 29, 2003
    Posts:
    104
    Likes Received:
    0
    Location:
    Nashville, TN
    [ QUOTE ]
    First, off, some of your ideas are not well planned out.

    [/ QUOTE ]

    That's why I like running these sorts of scenerios past those of you who may have already done them. /forums/images/graemlins/wink.gif


    [ QUOTE ]
    A 305 EGR carb is going to run LEAN at cruise without EGR. You will more than likely need to re-jet the carb.

    [/ QUOTE ]

    This is a crate motor -- how can it be EGR or non EGR? It's either, depending on how you configure it. The carburetor is an aftermarket Edebrock carb; not a factory EGR equipped carb from Chevy.

    Am I missing something in your statement? The non-EGR Edelbrock carb would be installed on a non-EGR Edelbrock intake on a GM crate motor. All of the pieces of the puzzle should match up. No?


    [ QUOTE ]
    Second, there is nothing wrong with the factory snorkel filter in almost all applications. Cold air makes more power than warm air.

    [/ QUOTE ]

    That's fine and one less part to replace/buy.


    [ QUOTE ]
    Getting rid of the "extraneous garbage" isn't always a good thing. If you are worried about passing a sniffer, you had better make sure that thing is running right after removing EGR, because if it's running lean and/or the converter is "worn out", you'll fail.

    [/ QUOTE ]

    Tennessee has a fairly lax emissions testing standard, but I agree that an engine running extremely lean will usually fail the sniffer test. Then again, an engine running extremely lean will also eventually start eating pistons so failing a sniffer is the least of your worries. /forums/images/graemlins/wink.gif

    The catalytic converter is a new high-flow cat, so it should be up to the task of baking off the excess hydrocarbons. /forums/images/graemlins/grin.gif


    [ QUOTE ]
    Unless thats a CA rig, then you won't have an ECM, although with that being a 305, I'm betting you have ESC. If you don't know this, you really should question whether or not you know what you are getting into.

    [/ QUOTE ]

    No, it's not a California truck and I'll double check for the existence of an ESC.

    I'm not a complete newbie when it comes to twisting wrenches and I've done several Ford engine swaps in my days of playing with Mustangs. But Chevies aren't Fords so that's why I'm asking all of these questions. /forums/images/graemlins/grin.gif

    Thanks for the answers! I need to do more research, obviously. The good news is that I've got a few Chevy guys who have all done engine swaps in older trucks helping me do this, so maybe they'll keep me from royally screwing things up. /forums/images/graemlins/wink.gif
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Sorry for the carb part, I read/saw the intake, skipped right over the next Edelbrock. /forums/images/graemlins/laugh.gif You are right, the engine isn't the determining factor.

    As to AIR, just the one pump. It more than likely won't work once disconnected (they freeze up) so if you ever plan on needing it (moving, visual inspections coming) it may be wise not to mess with it. That stuff is a ROYAL pain to put back on lol, even if just for a visual inspection.

    Is this a trail rig or DD? If trail rig, I don't know as your choice of carbs is going to be well liked by some of the folks that wheel. Everyone says the Q-jet runs better at angles, so thats something to consider for you if you plan on wheeling it.
     
  5. tungsten

    tungsten 1/2 ton status

    Joined:
    Oct 29, 2003
    Posts:
    104
    Likes Received:
    0
    Location:
    Nashville, TN
    No worries about the carb! I stacked a lot of questions in one post so it was easy to overlook something like that. /forums/images/graemlins/thumb.gif

    It's going to be a daily driver with minimal offroad use. Mainly just restoring it for sentimental reasons.
     
  6. tungsten

    tungsten 1/2 ton status

    Joined:
    Oct 29, 2003
    Posts:
    104
    Likes Received:
    0
    Location:
    Nashville, TN
    Allow me to ask another stupid question...

    If I were to use an Edelbrock intake and carb that *DO* support the EGR system, can I still run headers that do not have the AIR plumbing and also ditch the AIR pump?

    I guess what I am asking is whether or not the EGR system is tied into the other smog crap.

    Thanks.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Re: Allow me to ask another stupid question...

    EGR isn't tied into other smog stuff. EGR is pre-combustion, AIR is post combustion.

    On the carbed non-CCC trucks, I doubt there was ever an electric EGR solenoid like there is on at least some EFI setups. Lots of vacuum lines, vacuum and temperature switches to govern when it is applied instead.

    As long as the intake will accept EGR, you will be fine. Only time you run into problems is with aftermarket or late model heads that don't have the exhaust crossover, which means it has to be plumbed from the exhaust manifold/pipe to the intake or carb.

    The problem of course, is that all of that stuff, because of all the vacuum line t's are more than likely all interconnected. You could likely wade through them pretty easy though, trace where each goes, and remove only those that were applicable to AIR, and just eliminate any of teh extra t's.
     

Share This Page