View Poll Results: Which one should I go with
4” stroke with 6.125” rods
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Or factory stroke and rod length
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Rod ratio
Thread Starter
Teching In
Joined: Jul 2024
Posts: 1
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Rod ratio So this this my first ls build and I’m putting a lot work and money in to it and i am using a gen lll 4.8/5.3 block and I was looking for the rod and crack and I was think going with a forged crank that has a 4” stroke and the billet rods that are 6.125” long so the rod ratio comes out to be 1.53 would I have any issues with this set up and on another note I'm also using the tsp chopacobra cam and .660 dual valve spring and trying to find titanium valves and im using 7.400” push rod with LS7 lifter
Last edited by jake12697; Jul 30, 2024 at 04:24 AM.
I'll just say that running a factory throw crank and a 6.125 rod gives you a taller piston which equates to more piston in the sleeve. When running a 6.125 rod and a 4 inch throw crank the wrist pin is moved up higher in the piston to accomodate the stroke and the piston is a little shorter and they get even shorter depending on the stroke. Running a 4" crank in a Gen III block is not ideal due to the cylinder sleeve length but aftermarket parts are out there to build strokers and there's many of stroker motors out there.
Personally, if you can get a 3.875" stroke crank, I think it would be better in a Gen 3 block. The LS7 uses sleeves that are longer by........1875"-.250"?? Dont remember the exact difference. As mentioned above, longer sleeves help keep more piston in the bore at BDC. For a 50,000 mile engine it probably doesnt make a huge difference in longevity. But as the 10s of thousands of miles add up, it will make a difference, long term. My 02
