408 vs 418
02-20-2012, 09:19 AM
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408 vs 418 I am getting ready to order a shortblock and some heads. I can't decide what route to go. I am deciding between the 2 because of the 4" crank. I will use an LS3 intake and either CNC LS3 heads or some stage 2 or 3 LS6 heads. It will be a street only car. I want to get close to 500 on RWHP and also tq. Any thoughts, comments?
02-20-2012, 10:21 AM
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More cubes will alway yield better numbers
02-20-2012, 10:50 AM
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I just had my 408 done and it made 506/468 with a few hiccups. (slipping clutch and bad valve float that limited rpms to 5800and maxed out injectors) The build is an 11.1 comp. 408 with stock ls3 intake and a set of Scoogin Dickey's cnc'd ls3 heads with a mild 231/240 617/612 cam.My builder and tuner believe it'll make around 520/490 when everything gets straightened out.
02-20-2012, 11:12 AM
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ether one of them will fit the bill. a good cam in a 6.0 or 6.2 stock motor will belt out 480-495 you could do a livernois mini stroker 3.7?? stroke and get well into the 500rwhp range and save $2,000 or more. the less stroke means slower piston speed and longer potential life. If you got to have the 4" stroke then ether one of them will put you well over that mark. So your call. ether way you'll be a winner
02-20-2012, 11:27 AM
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you can do LS3 heads and stage 2 porting job for like 1800 its hard to beat that flow for that $$$ thats whats going on my G8 i'm going to end up with the mini stroker $3600 shortblock and through my 6L80E i'm looking around 500 with my Small No looping cam 
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02-21-2012, 04:20 PM
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I'd definitely stick with the LS3 heads. The ones from Sgoggin Dickens are THE best bang for the buck in a cnc'd head. $1,500 for a pair and flow numbers, especially on the exhaust side, that are very good. And they did very well in the head comparison's done in one or two of the car magazines.
If it were me, I'd stick with the 408 and put the extra $800 towards a FAST intake to go with the LS3 style heads. You'll have no problem meeting your horsepower goal.
What cam are you looking at? Compression? I would think right around 11.0 to 1 would be good and still be able to fill up at the pump. All the tests I've read and taken information down on show that relatively small cams make big overall torque and hp. Seems like lift in the .575 to .625 and durations in the 220-235 on a 113-115 LSA make gobs of power, idle pretty good and offer enough torque down low to pull like a freight train.
If it were me, I'd stick with the 408 and put the extra $800 towards a FAST intake to go with the LS3 style heads. You'll have no problem meeting your horsepower goal.
What cam are you looking at? Compression? I would think right around 11.0 to 1 would be good and still be able to fill up at the pump. All the tests I've read and taken information down on show that relatively small cams make big overall torque and hp. Seems like lift in the .575 to .625 and durations in the 220-235 on a 113-115 LSA make gobs of power, idle pretty good and offer enough torque down low to pull like a freight train.
02-21-2012, 04:29 PM
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I am looking at 11.5:1-12. Also considering the sdpc 427 L92. Just trying to validate the longevity of the 4.1" crank. Again this is for a pure non-abused street car. I just want a good scare once in a while!
02-21-2012, 10:44 PM
#11
I am getting ready to order a shortblock and some heads. I can't decide what route to go. I am deciding between the 2 because of the 4" crank. I will use an LS3 intake and either CNC LS3 heads or some stage 2 or 3 LS6 heads. It will be a street only car. I want to get close to 500 on RWHP and also tq. Any thoughts, comments?
02-23-2012, 07:25 AM
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ether one of them will fit the bill. a good cam in a 6.0 or 6.2 stock motor will belt out 480-495 you could do a livernois mini stroker 3.7?? stroke and get well into the 500rwhp range and save $2,000 or more. the less stroke means slower piston speed and longer potential life. If you got to have the 4" stroke then ether one of them will put you well over that mark. So your call. ether way you'll be a winner
