Milled 317 vs. L92 heads
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Teching In
Joined: Jul 2012
Posts: 13
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From: Des Moines, IA
Milled 317 vs. L92 heads I am new to this forum so please have some patience with me. I have just purchased a LQ4 out of a 2007 “Classic” 2500. Tore motor down last night everything looks good upon visual inspection. This motor is going into my rock crawler so building a motor that makes tons of power at 3K rpm and up is not suited well for my application. I have done a lot of reading and talked to some of the vendors on this forum. Should I mill my 317 heads down or just put L92 heads on motor? Keeping in mind I want good power but through a wide rpm band. I plan to keep the truck intake and my pistons are already fly-cut from factory.
MJC
MJC
The 317's are big chamber heads based of the LS6's. Like posted above they would be easier way to go for sure. The 02 LS6 cam picks these engines up a bunch for cheap reliable power. If you don't plan on running a custom grind.
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Verdad Gallardo Depends on the cam? If I was gonna mill them and run a low lift cam, .040"-.050", if the intake doesn't fit you just take few thou off the cathedral side. If you want a cam with more lift, you may wanna mill less... .050" mill with a .040" gasket on a stock lq4 short block should put you around 10.8 compression. I wouldn't want much more then that if you plan on going to Colorado climbing..
Last edited by MPFD; Jul 27, 2012 at 01:34 PM.
Lift doesn't matter with respect to p to v clearence, LSA and the icl matters more.
Regardless, a .030-.040" cut is doable without upsetting the intake port alignment. You will still need to check P to V clearence no matter what, but the smaller cams like 220/224 will be fine.
Regardless, a .030-.040" cut is doable without upsetting the intake port alignment. You will still need to check P to V clearence no matter what, but the smaller cams like 220/224 will be fine.
For good power throughout the power band I would do the 317s. The L92s have too big of a runner and valve to promote good low end power, especially if you can't get good compression. Small cam with good compression is a great recipe for a broad usable powerband.
It won't leak, that's BS. The intake will either fit or it won't. If it doesn't you just need to take about 10-15 thou off the intake sides of the heads that will put it back in alignment. I've seen guys that were buying pistons take over .060" of l92's...
An lq4 with a 212/218 .521 .520 114lsa would work fine with cheap Yellow LS6 springs. It would clear a a .040" mill and a .040" gasket easily. It will make a metric butt ton of torque up to 6000 rpm and be crisp and powerful right off idle. I'd run a truck intake for even more torque.
My stock bottom lq4 with 243's, truck intake and a patriot cam made 487 ft/lbs of torque with a 3600 yank and a 3.73 gear at the rear wheels...
An lq4 with a 212/218 .521 .520 114lsa would work fine with cheap Yellow LS6 springs. It would clear a a .040" mill and a .040" gasket easily. It will make a metric butt ton of torque up to 6000 rpm and be crisp and powerful right off idle. I'd run a truck intake for even more torque.
My stock bottom lq4 with 243's, truck intake and a patriot cam made 487 ft/lbs of torque with a 3600 yank and a 3.73 gear at the rear wheels...
Last edited by MPFD; Jul 28, 2012 at 01:40 PM.
