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2-bolt 350 block power limit

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  • 2-bolt 350 block power limit

    I have a good crank, rods and pistons for a 350 with JE forged dished pistons, a set of worked over Vortec heads, and a couple of roller cams with lifters that I picked up from a dirt track buddy of mine. One of the pistons is bad, so I do need to replace one of them. They are .020 over. I have a 350 2-bolt block standard bore that I could use; they only machine work it would need is the overbore for the .020 over pistons. I believe I will be able to put this motor together a a tight budget and make about 500 HP. When it was together, it dynoed 515 hp on 100 octane.
    Here's my question: I have little concern about the 2-bolt block holding up naturally aspirated; I do have a plate I would like to put on it, and that does concern me. First, can you safely spray a 500 hp 350 2-bolt block? Second, if you think its OK, how much? I currently run a Super Powershot solenoids (up to 150 shot), and have a set of Cheater solenoids (up to 250 shot).
    The other option I have is to run the 3.48 crank in a 400 block that I have. That, however, would take new pistons and a more machine work (my 400 block needs complete machining), and I'm not prepared to drop that kind of coin.
    The official Bangshift garage door guru. Just about anything can be built using garage door parts, trust me.

  • #2

    Re: 2-bolt 350 block power limit

    Re: 2-bolt 350 block power limit

    500 HP it will handle. (I think I read somewhere the limit is around 600 HP)-use some new ARP studs/bolts for the mains.

    I don't know if 150 or 250 HP extra is going to be a problem..
    -Some blocks were a bit stronger than others, -Have the block sonic tested if in doubt.

    Comment


    • #3

      Re: 2-bolt 350 block power limit

      Re: 2-bolt 350 block power limit

      Stock 010 cast (early big brg block) are 550ish.
      Add a set of ProGram splayed caps, a short fill and proper prep the block is good to 900hp.
      We have a couple making more than that but the blocks are walking around. At 1117hp we have had total block failure and pull the rear main and back of the block out.
      The 400 blocks are weaker than the 350 block due to thinning in the main webbing.
      We call then about 750.
      I alway suggest front and mid plates about 650hp for a sbc. Motor mounts not only distor the bores but can pull off the block. Plus front and mid should stiffer the chassis and help performance.

      Sure there may be super hero making more hp but, is it worth ruining everything else....

      Comment


      • #4

        Re: 2-bolt 350 block power limit

        Re: 2-bolt 350 block power limit

        This is going either in an 85 Monte or a 67 Malibu, both with 700R-4's and 12-bolts. They are 13.5 and 14.0 second cars currently. Right now I road trip both on a regular basis, but with this motor I will be making one of them more of a street/strip car. I'm leaning towards the Monte, since the rear in that one is a lot better, and it needs a new trans anyway. Long and short, I won't be filling the block or using a motor plate. Heck, I don't even have a cage. >
        The official Bangshift garage door guru. Just about anything can be built using garage door parts, trust me.

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        • #5

          Re: 2-bolt 350 block power limit

          Re: 2-bolt 350 block power limit

          It also matters the application. For road racing, I would not use a 2 bolt block over 450hp or an application where it will regularly turn over 6500. You start seeing fretting and on the main cap parting surfaces from the caps bouncing. Studs help a lot but on some engines you need to align hone the main bores after installing and torqueing them to maintain a concentric bore.

          For drag racing - sure no problem. I would use one up to around 550hp NA, if the RPM was not in the stratosphere, and there was no juice going into it. RPM is the worst for killing parts (its a geometric progression of forces where cylinder pressure is linear).

          I would throw a set of spayed caps on it for insurance personally or get a 4 bolt block.

          Comment


          • #6

            Re: 2-bolt 350 block power limit

            Re: 2-bolt 350 block power limit

            Detination is what kills those motors stay away from that, and you are ok
            2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
            First to run in the .90s .80s and .70's in SBN/A
            2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
            2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

            Comment


            • #7

              Re: 2-bolt 350 block power limit

              Re: 2-bolt 350 block power limit

              The guy that had been running these part in his NASCAR dirt modified turned it to 8 at the end of the backstretch. That was with a factory 4-bolt block with splayed caps. The cams he gave me measure around 680 and 715 lift with 1.5 rockers and I believe about 255 @ .050, I think, with a mean set of springs. I want to mock the valvetrain up and get exact specs. Those dirt track engine builders grind the part #'s off the cam. : Anyway, I was thinking maybe keeping it under 6500 or 6800. The dished pistons with those heads work out to 9:1, so detonation should not be much of a problem.
              He gave me what is pretty much a complete motor less block, rockers, and intake, plus a few extra parts (extra valve springs, push rods). He even gave me a Jesel belt cam drive set up. It was a good score for cheap.
              The official Bangshift garage door guru. Just about anything can be built using garage door parts, trust me.

              Comment


              • #8

                Re: 2-bolt 350 block power limit

                Re: 2-bolt 350 block power limit

                Get the right cam for your combo, rather than running something thats wrog because it was cheap.

                Comment


                • #9

                  Re: 2-bolt 350 block power limit

                  Re: 2-bolt 350 block power limit

                  That cam will not trap enough air for that low of comp and it will just start to work when you are quiting
                  2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                  First to run in the .90s .80s and .70's in SBN/A
                  2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                  2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

                  Comment


                  • #10

                    Re: 2-bolt 350 block power limit

                    Re: 2-bolt 350 block power limit

                    I know its way too much cam. That's why I want to run it. :P ;D My novice opinion is that the duration is not that terribly long, despite all the lift, so it shouldn't be too awful to live with. I helped my buddy with his Modified some, and it idled at 900. Sure, that's a cam for a lot more RPM, and maybe with some veteran advice I'll change my mind, but I kinda want to run it anyway. My brother sez to run something under 600 lift and more like 245 duration.
                    The official Bangshift garage door guru. Just about anything can be built using garage door parts, trust me.

                    Comment


                    • #11

                      Re: 2-bolt 350 block power limit

                      Re: 2-bolt 350 block power limit

                      You'll spend alot of cash replacing springs, and lifters for no reason. -keep the lift under 0.600 (or close to 0.600) -and with that low compression, you could easily run with 225-235 duration.

                      just my 2 cents..

                      Comment


                      • #12

                        Re: 2-bolt 350 block power limit

                        Re: 2-bolt 350 block power limit

                        Thanks for all the advice. I would like to put a motor together that will hang together for a while, at least, with minimal maintenance. Maybe I will go with something a little smaller, and lighter valve springs. Any suggestions for a cam? Vortec (non-Bowtie) heads, 2.05/1.60 valves. I'll probably run a Victor Jr or equivalant intake.
                        The official Bangshift garage door guru. Just about anything can be built using garage door parts, trust me.

                        Comment

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