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How much rpm and hp can a 400 small block handle?

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  • How much rpm and hp can a 400 small block handle?

    I have a 400 chevy 4 bolt main(weaker than 2 bolt) that has been rebuilt 30 over mabey 1,000 miles ago. How much power can this thing handle with stock internals. I want to build a low budget sleeper for my 75 nova 4dr and looking between 400hp and 500hp.

  • #2
    Re: How much rpm and hp can a 400 small block handle?

    500hp should be possible, if not easy, with the right heads and cam.

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    • #3
      Re: How much rpm and hp can a 400 small block handle?

      i have a z28 140 off road solid mech cam int .494 adv 304? .50 257 .Im not sure what heads to run though i have a set of world s/r or a set of 882 both have been pocket ported and have 2.02's, but i also for the price of having those redone i can get a set of afr 195 that are ready to go but im just worried it will be too much power for the stock internals. I also am going to run an air gap and a 750 duble pumper that i have.

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      • #4
        Re: How much rpm and hp can a 400 small block handle?

        Grind the parting lines on the rods, and polish them,
        plus replacing the rod bolts w/ ARP rod bolts,
        and maybe some ARP main cap bols. Cheap insurance.

        After grinding and polishing you may need a balance job,
        but that should be checked anyway if you replace pistons.

        If not, you should still have it checked.

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        • #5
          Re: How much rpm and hp can a 400 small block handle?

          Do you think bolts will be ok or should i go with studs, i want to do this really cheap, ?. Also i have heard about half filling it with block filler for extra strength is it worth it. I really want to cruise it around and flog it every once in awhile.

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          • #6
            Re: How much rpm and hp can a 400 small block handle?

            Originally posted by CooL-NeWeLL
            Do you think bolts will be ok or should i go with studs, i want to do this really cheap, ?. Also i have heard about half filling it with block filler for extra strength is it worth it. I really want to cruise it around and flog it every once in awhile.

            I'd stud it, but that may require having it align bored/honed.
            Depends on how much you got to spend.

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            • #7
              Re: How much rpm and hp can a 400 small block handle?

              This is going to be super cheap deal i really dont want to even take apart the bottem end. I think ill just get some good ARP bolts and forget the filler.

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              • #8
                Re: How much rpm and hp can a 400 small block handle?

                Originally posted by CooL-NeWeLL
                Do you think bolts will be ok or should i go with studs, i want to do this really cheap, ?. Also i have heard about half filling it with block filler for extra strength is it worth it. I really want to cruise it around and flog it every once in awhile.
                Forget he block fill you won't need it. And you want to get as much cooling as you can with a 400. As for bolt or studs depends on the price, I like studs, and if it's a few dollars more I'd go with them over the bolts.

                As for power I'd say your safe at 500hp.

                Go with the AFR's they'll make that 500hp goal a lot easier.

                Other than that I agree with Min301 on polishing the parting lines on the rods, it's just cheap insurance.

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                • #9
                  Re: How much rpm and hp can a 400 small block handle?

                  500 in a 400 should be easy
                  seen sbc with aluminum rods and light pistons shift at 12,000 rpm

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                  • #10
                    Re: How much rpm and hp can a 400 small block handle?

                    Originally posted by min301
                    Grind the parting lines on the rods, and polish them,
                    plus replacing the rod bolts w/ ARP rod bolts,
                    and maybe some ARP main cap bols. Cheap insurance.

                    After grinding and polishing you may need a balance job,
                    but that should be checked anyway if you replace pistons.

                    If not, you should still have it checked.
                    x2
                    we do a bunch of budget stuff this way "the devil is in the details" good hardware clean polish leave nothing untouched lol
                    the rods are strong just short
                    if it is a 406 or will be step up to a 5.7 rod it will wake it up over the 5.56 rod
                    let it breath is the keygood intake heads and cam just like any other engine
                    the lower will hold up with "factory"parts
                    my 400 i never fill and they always run around 195 temp wise even my 454 sbc runs cold temp will kill a 400 easy
                    my 440 was a 2 bolt with all the fun stuff my 454 was a 4 bolt 400 that is studded billet main caps and a girdle because it is the weaker block been in the car for bout 10000 miles so far and i punish it

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                    • #11
                      Re: How much rpm and hp can a 400 small block handle?

                      When I saterted working for VanPeenan, he had built a 406 of Ron Heeney
                      a few years prior. That was 15yrs ago, and that same motor is still in use,
                      though has been freshened a time or two.

                      I agree on the 5.7 rods, though that will bump up the price for balancing,
                      and require the use of new pistons(not a bad thing).

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                      • #12
                        Re: How much rpm and hp can a 400 small block handle?

                        Originally posted by min301
                        When I saterted working for VanPeenan, he had built a 406 of Ron Heeney
                        a few years prior. That was 15yrs ago, and that same motor is still in use,
                        though has been freshened a time or two.

                        I agree on the 5.7 rods, though that will bump up the price for balancing,
                        and require the use of new pistons(not a bad thing).

                        Don't think you need 5.7 rods, remember the stock rod is only .14 shorter, which is only about an 1/8 of an inch. Fact is you'll make more low end torque with the stock 400 rods with a little sacrifice to top end HP. Same thing goes for the 6 inch rod but in reverse, it'll make a little more top end power at the sacrifice of low end torque. As for the 5.7 rod it's in the middle making more torque than the 6 inch rod and more HP than the stock 400 rod.

                        Hot Rod or Car Craft did a shootout on the three rods and the 5.7 was best all around.

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                        • #13
                          Re: How much rpm and hp can a 400 small block handle?

                          not saying you need a 5.7 rod my first 2 406's were stock rods the 5.7 is a nice upgrade though

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                          • #14
                            Re: How much rpm and hp can a 400 small block handle?

                            Ill take the MIN advice and just polish the stock ones save myself some $. Im only looking at maybe 550hp at most, but i do have a nitrous kit but i dont think the stock 30 over pistons will handle that. Here is another question i have ran into from reading forums is not to use a high volume oil pump with a stock pan or it will suck the pan dry and cause damage. Any one have thoughts on that should i just get a good stock melling pump?

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                            • #15
                              Re: How much rpm and hp can a 400 small block handle?

                              Originally posted by CooL-NeWeLL
                              Ill take the MIN advice and just polish the stock ones save myself some $. Im only looking at maybe 550hp at most, but i do have a nitrous kit but i dont think the stock 30 over pistons will handle that. Here is another question i have ran into from reading forums is not to use a high volume oil pump with a stock pan or it will suck the pan dry and cause damage. Any one have thoughts on that should i just get a good stock melling pump?

                              Stock Melling, with a good pickup(retained), good oil pan and/or a windage tray should be all you need.

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