question on boring out a 5.9

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ETX Ram

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If i bore out my 360 to 408 do i have to get bigger pistons?
Short answer - yes. . .

If boring out 30 over (0.030), then need 30 over pistons to match.
If boring 60 over (0.060) then need 60 over pistons to match etc.

Good luck on your rebuild.

Lee
 

406shark

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If i bore out my 360 to 408 do i have to get bigger pistons?


Yes, if you bore an engine you have to buy pistons for the new bore diameter. By the way... you can't bore a 360 out enough to get to a 408. You also have to buy a "stroker" crankshaft to get the needed cubic inch.




Jeff
 

jo3gee

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If you want more power on the cheap, 30 over standard pistons will only get you to 365ci or so. But, if you get high compression pistons, that will help even better. The cubic inches wont go up, but hp and torque will. Downside is you’ll need to run premium gas.

Another quick and easy upgrade while you’re at it, would be a hotter cam, as long as you don’t go too crazy.

A stroker like a 408 requires many parts and even a budget build gets in the 1000s quickly done correctly.

This is my 408 in my jeep449eb23b33bcfeffbbcd000b4ff0e804.jpg
 
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PIPTHEREDRAM

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Awesome! Thank you. I'm wanting do some performance upgrades. Right now I'm working on modding my kegger. I'm wanting to do a complete ignition system and a cam. What cam would you guys recommend? (I haul fairly frequently so I want lots of torque if that makes a difference in cam size) also would I have to get me ECM tuned for those upgrades?
 

jo3gee

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I have used both crane cams and comp cams with great results. You will want to call them and ask for a recommendation based on your planned upgrades. They will pick the perfect grind for your use, and tell you if the choice would require a tune, bored throttle body, or different valve springs.

An upgraded ignition probably won’t yield big results over stock, just fyi. If it was my money, I would get the cylinder heads cleaned up and bored for larger intake valves instead, since you’ll have it off the block already.

There are many ways you can go, so get other’s advice and weigh it. Personally, if I have an engine tore apart, I’d rather spend money on it while I’m in there.
 
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PIPTHEREDRAM

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Alright thanks. I thought the cam was on the timing chain, why do you have to take the heads off?
 
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