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400 SB Rebuilt ? Your opinions are requested

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BurbinOR, Jun 5, 2000.

  1. BurbinOR

    BurbinOR 3/4 ton status

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    Guys, my 400 has a rod knock, I believe due to a fool of a mechanic allowing antifreeze to get into the bottom end and running the motor (no, not me! LOL). Can't prove it, but I think that's what happened. Anyway, have a choice to make - go with a crate motor or rebuild the 400. I MUCH prefer to keep the 400, but it was rebuilt once (.030" over). A guy I trust said it can be done up to .040" without any problems. Of course, it was only rebuilt about 40K ago, and may not need more than a honing. NOW, before the "400 motor heat problem" guys say it, that is a consideration. However, with my 4 row radiator and living in Oregon (moving this weekend) it NEVER has been an issue. ASIDE from the heat issue (maybe that IS such a big issue) what else do you guys think is a consideration? A crate motor is a guarantee of running well but have my old TPI/Vortech head compatibility issue to deal with (could get a motor without the Vortech heads I guess).

    Thanks in advance for the wealth of knowledge I am about to hear!

    <font color=blue>'79 K5 - 406 w/IROC TPI -<font color=orange> K5#5 - <font color=black>http:// www.blazzinor.coloradok5.com
     
  2. ken

    ken 1/2 ton status

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    Sell me the 400!! They are great motors no matter what anyone says. Heating is NOT a problem the way you have yours set up. A crate 350 will be lacking power compared to your 400...I know this from experience, having replaced a tired 400 with an RV cammed built 350, and the 350 had LESS power than the tired 400. "But parts are expensive for the 400...whine, cry, sniff, sniff!!!" HORSEPUKY!! The ONLY THING that is expensive (and not that much) are the pistons, and that is the only thing different (OK, the main bearings, but they're cheap!). How often do you buy pistons? OK, so the 400 pistons are $200 for the set and the 350s are $150...BIG FRIGGING DEAL!!!! No, on second thought, everyone please sell me their 400s, they are really bad motors, you know!!

    ken
     
  3. Burt4x4

    Burt4x4 3/4 ton status

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    Easy Ken..[​IMG]
    You know you want the HT383 Crate Motor....hehehee [​IMG]JK
    Just messin Bro
    I truly belive you are a diehard 400 fan!!
    Have good one

    Rock ON![​IMG] 72 K5 [​IMG] Led Zeppelin
     
  4. Andreas

    Andreas 1/2 ton status

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    Hummmm....I believe I was the one who started the "expensive sb400 parts" thingy. Well, I live in Sweden and a set of 400 pistons is 4 times as expensive as 350 pistons[​IMG]...and head gaskets is twice as expensive (for a few stinking stemholes!! Wonder if I should drill 350 gaskets instead).
    About BlazzinOR´s problem: I think you could get away with honing, if anything at all. I´m taking my 406 up to 0.060 (412[​IMG]) before I send it to the junkyard

    I will NEVER part with my 406 (Sorry Ken[​IMG])

    Andreas

    406cui of pure sh*t[​IMG]
     
  5. ken

    ken 1/2 ton status

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    Hey Andreas, why can't you mail order some pistons from the USA? Short of that, I or someone else could always buy them for you and ship em to ya!! Where in Sweden are you? I was in Orebro a couple years ago on business...actually Laxa at the ESAB Welding facility.

    And Burt, I am a diehard 400 fan, although have big blocks in all 3 of my GM rigs!! Only the wife's '90 Sub has a SB (roller cam 350!).

    ken
     
  6. Andreas

    Andreas 1/2 ton status

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    Ken ! It´s in the works ! Funny you mentioned it[​IMG]. I´m ordering stock pistons (well....030 over, but stock compression), roller lifters and roller rockers from a "friend" in the U.S of A. Trying to work out how to pay and sneak the package through customs, otherwise I´m looking at a 50-60% cost increase[​IMG] I hate taxes.

    I live 50 miles south of Stockholm, just by the ocean. Me and my Blazer[​IMG]. Sorry for taking up space in your post BlazzinOR[​IMG]

    Andreas

    406cui of pure sh*t[​IMG]
     
  7. dumbfounded

    dumbfounded 1/2 ton status

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    I'd just rebuild the 400. I've built alot of motors and the only one I ever bore out was my race motors. Every other one was just honed out, I look at it this way if you have the tools do it yourself. I screwed a bunch but I learn everytime. Look at what it will cost with 40k it probably only needs a hone. If the rod knock scratched the crank dump it and order one from summit or paw. I've been doing rebuilds for under $300 for years. The only one that was more than that was a twin turbo stealth that I broke the crank on. I did that for under $2000 including. engine lift, stand $400 gasket set, $800 crank, mains and rod brgs were over $300, and a few other things rings oil pump etc.
    Love your small block abundant cheap and with the 400 more power as for the heating the cylinder walls are thin and the more you bore them out the less metal to adsorb and dissipate heat. I've heard of a few builders that didn't like to go over .040 but its up to you don't bore unless you have to like scratches or just plane wore out. I don't think that a larger radiator would cure overheating problems with an over bored 400 I think it's localized boiling in the block around the cylinders but I could be wrong.... Personally I think a crate motor would be more expensive and dissapointing. If you don't have the tools to rebuild yourself the money you'd save would be more than enough to buy all you need and once you get the tools you'll always have them especially when you get bored of the 400 and need an 502........

    Wasn't me.............
     

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