350 stroker

Discussion in 'Small Block Tech' started by racenu, Oct 2, 2017.

  1. racenu

    racenu Well-Known Member

    Tried searching but no luck finding out if anyone has tried to do a 383 from a 350 buick or if It is even possible?
     
  2. alec296

    alec296 i need another buick

    370s have been built and a 380 is in the process. Cranks need a custom offset. You can use Honda journal rods to get offset . 6.400 or longer rods is what I suggest. Bottle neck is still heads. Big valves and porting to get atleast 245 cfm flow will open up potential. Derek has a lot of knowledge on the subject. Sonic test block for overbore. These blocks are fairly thick .
    Buyracingparts.com has done custom Pistons and special overbore head gaskets for these builds
     
    Gary Farmer and 300sbb_overkill like this.
  3. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Actually you don't want the rods any longer than 6.400" that is only .015" longer than the factory rod length because of cam clearance issues.

    The shorter the rod with the longer the stroke will actuate more away from the cam vs. a longer rods that doesn't actuate as much as it travels around the stroke at the main cap parting line on both sides.

    You can use longer rods though but attention to cam to rod clearance needs to be taken into consideration by either using a reduced base circle cam and or cutting clearance into the rod so it clears the cam.

    To build a sbb 383 you need to have the crank stroked to 3.990" for the use with the 1.850" rod journal size and an overbore of .105"which would only be 382.291 cid. Only taking the bore size .105" larger and not to the exact size needed to get to 383 is because rings have to be taken in consideration when going beyond the factory design parameters.

    You will definitely need to sonic check your block to make for certain that it will handle the extra bore size. Although the block we have sonic tested good for the .105" overbore, this probably isn't the norm for the sbb 350 blocks?(not sure, the first one I checked for this we got lucky so we didn't test anymore blocks at that time)

    Of coarse if you had a billet crank made with the stroke needed to get to 383 cubes with a lessor overbore that would be another way to get there.

    It would take an billet crank with a stroke of 4.160" to get to 383 cid with the basic .030" overbore. With a stroke this long though rods with a smaller journal would be a good idea because of cam clearance. The Mitsubishi rod journal size of 1.777" would be the next size down and being its a billet crank that size wouldn't be to small to stay together.(its the smallest rod journal size allowed in nascar, but I'm not aware of any teams using it at this time unfortunately)

    Since no nascar teams are using the Mitsubishi rod journal size, there are no nascar take out being sold on eBay so a custom billet rod would be necessary because the aftermarket off the shelf ones that size most of them are under 6" long with only IIRC one set that is only slightly over 6" long.(let me check, I'll be right back) Looks like the longest 1.777" off the shelf rod journal size rods are 5.967" long.(would be good to use for a stroked sbb 300 crank but to short for the sbb 350)


    The reason the one we have is only going to end up as a 380 is because 2 cranks were taken to the crank shop with one of them already .020" under so the guy did the undersize one first and without asking made the second one the same!!!:mad:(still makes my blood boil thinking about that!)


    If in you're interested in building a sbb 350 stroker and want more info, feel free to ask, I'm happy to help. GL
     
    Julian and Gary Farmer like this.
  4. Extended Power

    Extended Power Well-Known Member

    My son and I just finished a 373 Stroker.
    If it wasn't for the members here, who wanted nothing more than to see this engine come together, it would never have happened. (Sean, Derek, Marty, and Gary to name the party of four.)

    I can't believe how much torque it has...we are actually thinking of putting the 3.08:1 gears back in, as the 3.73's are like driving on ice all the time.

    Crank was offset ground= 3.990"
    Carrillo NASCAR take out rods= 6.450"
    Block was bored out to 3.860" (.060" over)

    Had lots of "Interference" between the roller cam, and the rods...had to clearance every rod.
    Roller rockers had to be clearanced.

    Took a long time to get it all together.....it's almost funny how everything was fight...nothing was easy....except spending huge amounts of money.
     
  5. sean Buick 76

    sean Buick 76 Buick Nut

    The major issue with the stroker deal is that not all machine shops can do the work properly. Our friend above had a crank custom machined and it turned out totally wrong and just went to the trash bin after mega $. Only once I provided a mint virgin crank without wear could a new shop get it right. Not many virgin mint cranks around to maximize the stroke.

    The best way to stroke a 350 in my opinion is to use a king billet crank with 1.77 rod as Derek suggests. But if you do that you may as well do a block girdle...

    I have never been a fan of stroking or boring the 350, but each to their own.
     
    ceas350 and Extended Power like this.
  6. Extended Power

    Extended Power Well-Known Member

    Greatly appreciate you selling the crank to us Sean...and for dropping it off at the machine shop!
    And giving us a set of heads for the price of shipping them!

    Incredible amount of knowledge, help, and talent outta this camp!
     
  7. sean Buick 76

    sean Buick 76 Buick Nut

    No worries the end result is awesome, very nice attention to detail! I would love to see it on a chassis dyno...
     
    Gary Farmer likes this.
  8. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    The dyno program showed big block torque on it, like around 430 or 440 ft. lbs. if I recall correctly, and about that much hp.

    Quite impressive for a Buick 350 (373), I'd say.

    Thank you for the commendation. I love to see it all come together with the excellent results.

    Stroker engine with good flowing heads and a roller cam are key to making big power.

    You can see that without perfect traction, torque multiplication reduction (such as with lower 3 series or high 2 series gearing (3.08-2.73) will improve street performance--just be careful because you'll be going 100+ MPH before you realize it.

    This was the case with a car I had that used a powerful 455, a ST300 2 speed trans, and 2.93 gearing. Traction was still a problem, but man was it FUN.
     
  9. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    From what I've gathered from the information here on the boards from knowledgeable members on the subject, the Buick 350 generally has plenty of 'meat' in the block and can be overbored well past .060 (sonic test a must) and using custom pistons and offset ground crank, displacements of 380+ are achievable.

    With the extra cubes flowing through good heads and a roller cam, will really transform these engines.

    TA stands to make some serious coin on this combination theme as more and more engines are being built and the results posted here for the world to see.

    You guys better grab up all the Buick 350's you can get your hands on, because the popularity and value on these engines are about to explode (if my predictions come out to be true), along with the forced induction combinations (think Grand National with 2 extra cylinders and much more stroke on the engine).
     
  10. Mart

    Mart Gold level member

    Must be that 3,500 stall! Need street slicks. Just don't drive on wet roads. :D
     
    Extended Power likes this.
  11. racenu

    racenu Well-Known Member

    This has been an interesting thread, I never hung out in the 350 section and am seeing some intreaging information. A nieghbour down the street in Phoenix is always buying and selling cars that need a little tweaking or tinkering. At one point he had 4 Chevys in his garage and they all had 383 strokers, and he made a point of getting me to stand by the tailpipes while he reved the engines, I have to admit I liked the fact they reved quick and sounded pretty sweet...for a Chevy that is.
     

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