416 build, head and intake ?
03-31-2011, 11:56 PM
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416 build, head and intake ? Ok, I am planning to build a new motor for my car (1993 mazda RX7) I presently have a Stock bottom end 5.7 with a set of TEA LS6 stage 2 heads. I am attaching flow sheet. The TEA Stage 2 LS6 243 castings come CNC ported with Ferrea 2.04" intake and stock 1.55" exhaust valves, have 225cc runners and have been milled .020" to give a 61cc combustion chamber. I am running a set of Patriot platinum dual springs and yella Terra ultralight 1.7rockers. I currently have a comp XER cam 232/236, 595/601, 114+4. I have 1 ¾ long tube headers and a stock ls6 intake with mildly ported TB. This is mated to the stock F body t56 tranny and will be mated to a ford IRS with a 3.73 gear.
What I am planning on building is a LS3 block with a LS7 4” crank and factory LS7 titanium rods mated to custom forged pistons designed for those rods and stock 4.065 bore to make a 416. I have the rods and crank and a guy that makes the pistons. I will eventually need final specs for height of pistons and valve reliefs but that will come after head selection and cam selection. This is where I was needing some advice. Given the heads I have and the newer heads available (intakes as well), should I start from scratch with a different set of heads or will the heads I have work. The flow doesn’t seem bad but will most likely benefit from a different intake. For the money that will need to be spent on a better intake for the cathedral port ls6 heads, (i am assuming fast is the only option here, which one?), would it be better to spend it in the heads. My buddy has an LS3 intake that he is not using but it would require new LS3 based heads. I would imagine that cam selection is going to change no matter which way I go with heads. from what I can tell, my heads are better than stock ls3 heads but possibly under ported ls3 heads. I could sell my heads to pay for new ones and probably get away with about as much out of poket money as I would spend on a new inatke. assuming the ls3 only cost me $100 or so. I also understand that the flow #'s I posted are probably on a 3.9 bore and would be even higher if they were flowed on a 4.065 bore so I wonder what they are really like compaired to those ported ls3 heads.
I do not drag race and prefer a setup the is softer on the bottom end. I want to be able to turn 7k and not beat up the valve train. I turn 7k now and that is why I will be using the LS7 rotating assembly. Will never see NOS or boost. Looking for the best value for performance vs cost. Cams will cost the same so I guess it comes down to which way to go on heads and intake. If I keep my heads and change intakes and cam, how much am I leaving on the table vs all new heads and LS3 intake. don't want to buy new heads and new fast intake. its either ls3 intake and corresponding good rectangular port head, or my heads and better intake.
Mike
What I am planning on building is a LS3 block with a LS7 4” crank and factory LS7 titanium rods mated to custom forged pistons designed for those rods and stock 4.065 bore to make a 416. I have the rods and crank and a guy that makes the pistons. I will eventually need final specs for height of pistons and valve reliefs but that will come after head selection and cam selection. This is where I was needing some advice. Given the heads I have and the newer heads available (intakes as well), should I start from scratch with a different set of heads or will the heads I have work. The flow doesn’t seem bad but will most likely benefit from a different intake. For the money that will need to be spent on a better intake for the cathedral port ls6 heads, (i am assuming fast is the only option here, which one?), would it be better to spend it in the heads. My buddy has an LS3 intake that he is not using but it would require new LS3 based heads. I would imagine that cam selection is going to change no matter which way I go with heads. from what I can tell, my heads are better than stock ls3 heads but possibly under ported ls3 heads. I could sell my heads to pay for new ones and probably get away with about as much out of poket money as I would spend on a new inatke. assuming the ls3 only cost me $100 or so. I also understand that the flow #'s I posted are probably on a 3.9 bore and would be even higher if they were flowed on a 4.065 bore so I wonder what they are really like compaired to those ported ls3 heads.
I do not drag race and prefer a setup the is softer on the bottom end. I want to be able to turn 7k and not beat up the valve train. I turn 7k now and that is why I will be using the LS7 rotating assembly. Will never see NOS or boost. Looking for the best value for performance vs cost. Cams will cost the same so I guess it comes down to which way to go on heads and intake. If I keep my heads and change intakes and cam, how much am I leaving on the table vs all new heads and LS3 intake. don't want to buy new heads and new fast intake. its either ls3 intake and corresponding good rectangular port head, or my heads and better intake.
Mike
