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Doing some stupid shit to an old datsun head

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    Nah, scratch, slipped.

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      Jesus H Christ the exhaust ports on these things are a massive PITA.

      Working back tonight, I the porting all done before I knock off, including the intake manifold.

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        Have you seen a round exhaust port version. I got great power from one years ago but there so rare.
        GURU ENGINEERING PTY LTD

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          I want to do one of the six cylinder heads with the cast in liners and do a D shaped exhaust port with a raised floor, but I don't have any time for another project at this point.
          Edit: Looks like there's a four banger with the cast exhaust port liners too.

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            Ah, I see why you needed rings now!

            I have a partial set of Nissan L6 rings, 87mm, but I am missing the 2nd rings from the set. I am not sure I'd be using them for something like this, but I am certain I'd be running an 88mm bore if I could cram it into the block. (I run 88's in most of the L6's I have here) Overbore limited or are you going for the gold on bore?

            Hoping to finish up my flow-bench and have a go at some of the ideas you present here. I've got a few U67 castings set up on the shelf, along with several P90 and N42 heads, and a couple Maxima/DR31 N47's with the small chambers and ports. We didn't get the 05L or Y70 castings here.

            Still need to get the car back together for some dyno time, before I yank the head off again and touch it up!

            Not sure why the roundport heads come up...they're pretty well shunned here for anything other than moderate street setups. Most I've gotten from a roundy-port head is 138CFM exhaust, which is not bad a is very close to what I can get out of my best squareport...which will do 144CFM so far. I think TK's just blown that out...I'd guess 150-155CFM exhausts?

            Intake ports, best I've done is a 40mm port/44mm valve that touches 250cfm at 0.550" lift, on a P90. Those ports look bigger and straighter, straighter by far. What do you think you'll make with this one?

            I'd say on 45mm ITB's, and a 2.0L bottom end, at 14.5:1 compression, that 260HP or better churns out the end of the crank. Any other guesses?

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              About 240-250hp is the highest HP aspirated L20B I've heard of.....

              Not gonna guess on this one, but I'd like to think she'll make some pretty decent numbers.

              Best previous exhaust port I've done was 150cfm, I need to beat that, I need 170.
              Only need 230cfm intake (through the TB's & manifold) to get where I want to be, so it's gonna be the exhaust that kills the fun if anything.

              All done with the porting on the head (bar sanding), just about to strip down the intake & fit it up to the head.

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                Highest I've ever seen was 221 at the crank, was on 48mm DCOE's and had a domed piston for 14.2:1 compression, as claimed. I didn't get to see anything but the finished engine run on the dyno. Was wound pretty tight, but I have a racer in the northern part of my state running one at 11,000RPM through the traps at the end of the quarter mile. I keep telling him to shift up...he's not bought that fifth gearset though.

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                  Originally posted by TK View Post
                  Jesus H Christ the exhaust ports on these things are a massive PITA.

                  Working back tonight, I the porting all done before I knock off, including the intake manifold.
                  Have a look at the Mark Banyard contact thread you started. The last pic is the way to exhaust port enlightenment
                  Looking for 86 GSXR bits. PM me

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                    Yeah, I know, but there is no time/budget for even more radical surgery!

                    I reckon we'll be right, got the exhausts pretty damn good - can't flow it, guides are not in the right spot yet, may get a chance tomorrow arvo.

                    Got the intake manifold all ported & sanded up, intake ports in the head sanded & started on the chambers, but it ain't gonna happen tonight, been porting for 14 hrs today, had enough!

                    Pics tomorrow arvo I reckon.

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                      14 hours Man, that's above and beyond

                      Sometimes think I should have given you the crappy flowing VG30ET (single cam) heads I had. Just to see.
                      Richard's DatsunZ lappin LakesidZ http://www.youtube.com/watch?v=47OSh...&feature=g-upl

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                        https://www.facebook.com/groups/down...9491313736800/

                        Some people aye.

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                          You have to be a member to see it?
                          "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

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                            O someone link the race magazine write up and the Peter MC guy say it's old work done by others years ago.

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                              stupid internet argument. carry on.

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                                Lol just read the Datsun fb page this morning, fuck the Datsun community is a toxic shit pile
                                Originally posted by Walt Kowalski
                                Memes are only detectable by NSA.

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