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what size for dual exhaust on TBI 350

Discussion in 'The Garage' started by S10K5, Feb 10, 2005.

  1. S10K5

    S10K5 Registered Member

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    I'm looking to run dual exhaust on my rig. What size tubes should I run? The motor is a TBI 350 and it is fairly stock for right now.
     
  2. 1977k5

    1977k5 3/4 ton status Vendor

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    2.25" for duals. Anything more is unnecessary (and quite a bit more expensive).
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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  4. mightywhitey_k5

    mightywhitey_k5 Registered Member

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    ya 2.25 is what i ran on my 350 TBI with dules and it is perfect, i also ran flomaster mufs. and freeflo cats. it is a good set up like that. the only thing i recomend is headers my 87 didnt pick up hardly any mpgs or power because i havent put headers on yet.
     
  5. S10K5

    S10K5 Registered Member

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    thanks a lot for the input. Have any idea who would have a good price on Cats?
     
  6. 86chevybanshee

    86chevybanshee 1/2 ton status

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    on ebay you can get high flow cats for under 50$ each
     
  7. beater_k20

    beater_k20 Banned

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    2.25" is more than adequate. i'm seriously looking into a 3" single system, flows just as well, should be cheaper to do, and less things hanging from the underside of the rig is better.
     
  8. divorced

    divorced 3/4 ton status

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    I'm with you on this. When I had my duals put on it was $400. That was for 2.25 or 2.5, so I went with the 2.5

    If I ever build the motor up some or put in my 454, the exhaust will already be there.
     
  9. xtrmjoe

    xtrmjoe 1/2 ton status

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    Go single 3".
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Not to be the lone stick in the mud, but if you need to pass a visual inspection, you *should* fail for dual cat converters as they were never offered in any combination of the vehicle you have. :) just not sure what your end use of the vehicle is, and whether there are visuals in Phoenix, I thought there were.

    That said, I'm coming around to the single 3" way of thinking anyways...less parts, less cost, less things to go wrong, all the performance.
     
  11. highrlr

    highrlr 1/2 ton status

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    What do you guys that run a single 3" do with your crossover pipe? My factory one on my '89 hangs pretty low but it looks like if a guy put it up tighter to the tranny you would have troubles removing the tranny pan or the inspection cover on the front of the tranny. Another concern i have with the factory x-over is does it add any unnecasary(spelling?) heat to the tranny, what if a guy wraped it with header wrap? Maybe im just worrying too much? And is the factory diamater pipe fine for the x-over? Oh and what would the best set of headers be for a fairly stock ( just bolt ons) TBI 350? Sorry if im highjacking the thread:confused:
     
  12. S10K5

    S10K5 Registered Member

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    Thanks a lot! All in all, dual would be cool but I think single is the more practical way to go. (and I do have to have the vehicle inspected prior to registering it)

    Thanks everybody.
     
  13. blackblazer717

    blackblazer717 1/2 ton status

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    i would go 2 1/2 max thats plenty but i like 3inch single

    luke
     
  14. dirtwarrior17

    dirtwarrior17 Banned

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    mild hijack.....


    I run afterburners with the afterburner y pipe connected to a 3 inch single and it sounds damn good. The afterburner y pipe runs about 3 inches higher than my front 10b and you can get the pan off easy with it on. Not sure which came with collectors but i ended up with two off em... you can weld em on the exhaust and y pipe then just bolt the two together(comes with 3 bolt flanges) so its easy to take it on and off if your tranny hangs further than my 700.

    Only problem is the coating comes off right away, or it just came off becuase of the new motor. Its cheap coating tho.
     
  15. Hossbaby50

    Hossbaby50 3/4 ton status

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    I have actually passed emissions here in Phoenix for the last 7 years or so with true dual exhaust even though it is illegal. They don't seem to care at the emissions stations. It is a no no, but they don't mind I guess.

    If you are going threw and inspection then I wouldn't press my luck with duals. A good 3" system is plenty for a stock to mild SBC. If I was going to do duals I would do 2.25" with mandrel bends or if 2.5" if you can't get mandrels.

    I personally have 2.25" without mandrels. It does good but I think could do a little better with some mandrels or going to 2.5". I have a mild SBC.

    Harley
     
  16. mini_mull

    mini_mull 1/2 ton status

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    The burb I just bought has true duals (with dual cats, obviously), and has passed Maricopa County inspections for years like that. I guess the people working inspections either don't care or don't know it's not suppose to.
     
  17. Jonny-K5

    Jonny-K5 1/2 ton status

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    from what i've heard AZ is pretty laxed on the visual inspection department. i still think a single 3" is the way to go.it'll flow more than dual 2.25 pipes.more than enough for any 350 tbi. i'd go with thorley headers, high flow cat, magnaflow muffler, madrel bent tail pipe. someone on here sells exhaust stuff cheap, i think its muddysub, but i cant remember for sure, whoever it is, thats where i got my cat and muff, good guy and cheap prices.

    i was worried about my y pipe hanging so low too, but i've found that the Tcase always hits first on breakovers anyway.this is, unless your dragging the truck over boulders .
     
  18. AussieK5

    AussieK5 1/2 ton status

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    Couldnt agree more, on my last K5 I fabbed up a single 3" system in a buddies muffler shop that was simple, much cheaper and so much less hassle. I'll be doing exactly the same to my latest truck.
     
  19. bear76

    bear76 1/2 ton status

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    The replacement exhaust I got from nappa, cat-back, was 3".? I have a 91 and it showed this was the stock size. With thier muffler (could be replaced w/ flowmaster,cherrybomb..) was $210.00 including all the clamps.
     
  20. muddybuddy

    muddybuddy 3/4 ton status

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    yep stock exhuast on 87-91 was 3", i didnt know that either til i did the same thing u did.
     

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