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Discussion in 'SVT Shelby GT500' started by boduke0220, Oct 10, 2018.

  1. boduke0220

    boduke0220 Well-Known Member Established Member

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    Looks like my rings are done. I want to do a set of rods and pistons, maybe a set of cams too.

    my issue is this.

    I don't want to sacrifice reliability. I enjoy messing with these cars, but I don't want to be fixing something every weekend if I put a built motor in. I want to be able to drive a couple hours to the beach without worry that something will happen. is this possible? Ive never had a car with a built motor so im not sure if I am asking too much.

    thanks!
     
  2. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    Much of what you do depends on how you intend to use the car. A built engine shouldn't be that much different than a stock engine, just better components. But then my concept of a built engine has more to do with a bulletproof bottom end than airflow modifications and cam selection. Most built engines end up being race builds which usually have looser clearances and more aggressive cam timing. Nothing wrong with that, but there are trades offs driving a racing engine on the street. When you start turning up the wick with more aggressive cam timing, you really need to upgrade a lot of the cam drive components, if you want it to be reliable. It gets expensive fast. If you want reliability, I'd stick with the stock cam and valve springs or possibly a very mild cam upgrade that is capable of using the stock springs. My cams are not that bodacious, but it still only idles with 12 hg of vacuum with 44 degrees of overlap at the valve.

    The gearing for these cars was intended to work with very mild camshafts. The top gears are intended for pretty low revs, which will give an aggressive camshaft fits. Not a big issue if you travel fairly level highways, but if you contend with a lot of grades, you may be working that shifter between fifth and sixth more than others in the plains. Even in mild form, these engines are capable of making more horsepower and torque than you can harness anyway. If you're looking for a true driver, keeping the valve train close to stock and doing other mods that improve air flow, like porting the lower manifold, a better supercharger and fuel mods. Even the stock pistons are good pieces, but the rods are the real weak sauce in the bottom end.
     
  3. boduke0220

    boduke0220 Well-Known Member Established Member

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    Yes, looking for a true Driver! I was thinking some L&M NSR cams, H beam rods and basic pistons. I don’t want anymore than 800rwhp. It’s a daily so any more than that is just pointless
     
  4. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    L&M's NSR cams are a bit more radical than what I was referring to above.
     
  5. HandBanana

    HandBanana Well-Known Member Established Member

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    If you don’t push that newly built motor to its limit, you should be fine. If it’s an aluminum block car, I’d sleeve it while the motor is out. I think it’s around 1800 to do. Sleeves, rods, pistons, head studs, bearings, etc should put you around 5k if you wheel and deal for pricing.

    Good fuel is key. E90 ignite is good stuff.

    I’d keep it around 850-900whp if you want it to last. 1000whp = unreliable in the long run. Constant maintenance. Good rule to live by with motors: don’t push it if you don’t want to push it(off the road )
     
  6. boduke0220

    boduke0220 Well-Known Member Established Member

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    Thanks for the input guys, maybe I will skip the cams then. 800rwhp is all I am really after. I have a truck, but if its not raining this car is on the road. Maybe I will put the cam money into another area like a good twin disk and/or port the blower.

    Definitely going with E85 as we have a ton of it where I live. just trying to swallow the price of ID1300's at the moment lol
     
  7. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    Here's a chart of BJ's (VNMOUS1) GT500 from an article here. The only difference between these two pulls is the installation of the L&M cams. No doubt, these cams make great power on the top side, with the coveted lumpy idle, but look at the impact in the area I circled. These are typical rpm ranges that you'll encounter on the street, although not necessarily at WOT. What you don't see is the impact at even lower rpm. I can't speak for the exact rpm ranges at lower rpm, but I doubt these cams would be happy at less than 2,000 rpm, possibly more. In my car, with 3.73s, that's 85 mph. Can it be done at lower rpm, sure, but expect to downshift a lot.

    I drive my car mostly on the street, but it is not my primary driver. I've been wrenching for almost 50 years, so I have made my fair share of camming mistakes. Swapping out cams in an old pushrod V-8 is a cake walk compared with the modular, so they're not so easy to remedy if you don't like the drivability. The end result in this case is a gain of 60 horsepower on the top end. But with even the mild stock cam, you're not going to hook up all that well with 850 rwhp and 825 lb. ft. of torque. The cams in your 2013 are a bit more aggressive than those found in the stock 5.4 too.

    2017-05-31_19-29-35-640x968.jpg
     
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  8. boduke0220

    boduke0220 Well-Known Member Established Member

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    That's really good info man, I appreciate that. down 80 foot pounds, no thank you. I had a Whipple Coyote making 850rwhp before this car and one thing I really love about the 5.8 over the 5.0 is the stump pulling torque.

    The guy I take my car to said he could Put the rods and pistons in for around $1500-2000. So that's good. if I can get out under $5k id be tickled to death.
     
  9. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    I'd recommend spending the money for ARP fasteners, where practical, on your build.
     
  10. Sielmo

    Sielmo Active Member Established Member

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    I wish I saw this before I went down the Cam journey I chose. In the end, I'm back to stock and very happy. All that you describe is exactly what I experienced...then again, you know that already!
     
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  11. VNMOUS1

    VNMOUS1 Well-Known Member Established Member

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    Dropping that torque was important in my case. Much easier to hook it and more than makes up for it on the big end.

    Sent from my SM-N950U using the svtperformance.com mobile app
     
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  12. Klaus

    Klaus Well-Known Member Established Member

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    Going through same exercise as OP. Going back and forth on cams. Power goal is 850. Even if I stick with stock cams would you recommend putting in new springs and retainers?
     

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