500+rwhp 346?
07-03-2005, 02:13 AM
#4
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for a street car, good luck. granted anything is possible, but its not too probable. i would say milling to get 11.5-12:1 plus huge ports, huge cam, and a bunch of lil things: polishing or painting lifter valley, knife edge and polish all surfaces of crank, nice windage tray, etc, etc, etc. i personally dont think u need new internals but modified stockers.
07-03-2005, 02:38 AM
#5
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polishing or painting lifter valley
Basically, I know solid roller systems haver achieved that 500rwhp mark..
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07-03-2005, 08:16 AM
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I wanted to try and do it n/a. I was gonna save up and build a big cube motor in a year or two but the the vibration that the car has had is a miss (how i missed it i have no idea but i did, wrote it of as being the lope of the cam cuz the idle held smooth arount 875). I going to do a compression test and see which it is and then im going to test the coils. Just prepareing for the worst and i cant afford a big cube motor right now. My goal will be 10's with no spray.
07-03-2005, 11:22 AM
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Call TTP, they have done it with stock cubes. It will require a Big Big Cam with a lot of work on the heads and good tuning, plus all of the bolt ons and a little luck.
07-03-2005, 11:27 AM
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I would start with a forged 402. Bigger gets much much more expensive. You will much happier (The car will be more drivable, reliable, with 80 more torque, and the torque will start earlier). What I have seen lately, the price will not be too much different than will built 346-348 forged motor.
07-03-2005, 01:34 PM
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A good pump-gas engine can make about 1.25 FT/LBS of TQ/CID. That means a 346 on pump-gas will make max torque of about 432. Another trend I've noticed is that there is generally a 10-12% loss of peak torque at peak HP. So let's say our goal is 500HP. At 500HP we'll have about 380 FT/LBS of TQ. Now I plug-in my Peak HP number and my Torque @ Peak HP number to figure out how many RPM I'll have to turn. I come up with 6,900 RPM. Perfectly capable for a stock bottom-end LS1 car. 
Keep in mind these are all ball-park figures. They are also on the conservative side of things.
Keep in mind these are all ball-park figures. They are also on the conservative side of things.
07-03-2005, 02:11 PM
#16
A more aggresive cam in my C5 and I would have been knocking on 500 RWHP with out of the box 205's and a little over 11 to 1 CR. (Granted it has ALL the bolt-ons, a very "optimized" package, and a lot of time invested in the tune). Add some 225's to that aggressive cam mentioned above and cresting over 500 would have been a no brainer. Unfortunately, the small chamber 225's aren't finished or I could have provided you with hardcore facts from a dyno, not just my opinions. Look for that in the months to come (both the heads AND the dyno tests).
What people fail to take into account is what the finished product is all about. It's not going to be ideal for a daily driver, and some people might feel it's even to aggressive for a dual purpose car (while others will find it to be just fine). What most people will not consider is that the engine will want to turn big RPM's....thats were the "power" will be made. Peak TQ will be similar to other milder H/C cars (assuming CR is close) but the TQ curve will hang much better in the upper R's, hence the increase in power output. What that means is you better have a dialed in valvetrain that wont float the valves (difficult but doable with the right Hyd. set-up), or just step up and put in a solid roller which has superior valve control at high RPM's. Now take a look at the shortblock...do you really want to spin the factory shortblock to 7300 or so (even WITH better bolts)? Ideally an aftermarket rod and piston would be warranted....now that the shortblock is opened up doesn't it make a lot more sense to put a stronger 4" crank in it....
You get the picture....Making 500 RWHP (out of 346 inches and a reasonable CR) IS achievable....whether the finished engine is really what you want or remotely cost effective is a whole different topic.
Just my .02
Tony M.
What people fail to take into account is what the finished product is all about. It's not going to be ideal for a daily driver, and some people might feel it's even to aggressive for a dual purpose car (while others will find it to be just fine). What most people will not consider is that the engine will want to turn big RPM's....thats were the "power" will be made. Peak TQ will be similar to other milder H/C cars (assuming CR is close) but the TQ curve will hang much better in the upper R's, hence the increase in power output. What that means is you better have a dialed in valvetrain that wont float the valves (difficult but doable with the right Hyd. set-up), or just step up and put in a solid roller which has superior valve control at high RPM's. Now take a look at the shortblock...do you really want to spin the factory shortblock to 7300 or so (even WITH better bolts)? Ideally an aftermarket rod and piston would be warranted....now that the shortblock is opened up doesn't it make a lot more sense to put a stronger 4" crank in it....
You get the picture....Making 500 RWHP (out of 346 inches and a reasonable CR) IS achievable....whether the finished engine is really what you want or remotely cost effective is a whole different topic.
Just my .02
Tony M.
07-03-2005, 02:29 PM
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I was trying to do that.. but I decided to spend my money once and build a 408 instead of throwing all my money at a 34x engine and doing a 408 later on down the road. If you ever drive a 4xx cubic inch car, you'll never pour money into a 34x normally aspirated car.
07-03-2005, 10:01 PM
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Originally Posted by gomer
I was trying to do that.. but I decided to spend my money once and build a 408 instead of throwing all my money at a 34x engine and doing a 408 later on down the road. If you ever drive a 4xx cubic inch car, you'll never pour money into a 34x normally aspirated car.
Tony has several well written valid incites as well.
Even though my new motor will spin and pull up to 7,300. I think we will cap it at 6,800. The new oiling system will be constant consistant pressure around high turns with 13 quarts of Mobil 15-50 in the system, curtesy of Ron Davis, DRM and Accusump.
07-03-2005, 10:21 PM
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I agree, for what i paid for my forged 347 ( and trust me i got a deal ) i could have had a 402 today with a lot more tq. Unless im just freshening up a shortblock for a big shot of funny gas or boost, id definetly go bigger c.i if your intention is to be N.A. I have never been in a big cube LS1 but i can only imagine...some day.