can a forged 346 or a forged 370 handle more boost?
06-22-2010, 11:54 PM
#1
can a forged 346 or a forged 370 handle more boost? im debating whether to forge my stock bottom end ls1 or take a 6.0 iron block and punch it .30 over and make a forged 370 cubic inch bottom end........im aiming for about 700-800 rwhp. whats better? should i stick with the motor i have and save some money? thanks guys!
06-23-2010, 01:22 AM
#3
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I believe a 370 weighs around a hundred lbs. more. Thats a chunk up front. All depends on how much boost your looking at throwing at it. What are your plans?
06-23-2010, 06:58 AM
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What the hell is up with this site lately?
he wants 700-800 whp. you will be fine with a forged 346. anyone that tells you to go iron block for 800 whp has no clue what they are talking about.
he wants 700-800 whp. you will be fine with a forged 346. anyone that tells you to go iron block for 800 whp has no clue what they are talking about.
06-23-2010, 08:46 AM
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There was a guy in gmht mag that had a forged 347 and twin mp70s, on pump gas he made like 800 or so but on race gas and upping the boost he made 1004 rwhp so I'd say a forged ls1 would work fine...
Although it is for some reason Easter and cheaper to go a little bigger
Although it is for some reason Easter and cheaper to go a little bigger
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06-23-2010, 09:08 AM
#9
This argument gets heated. I have of course a forged 408 iron block and wanted to be able to do around 1000rwhp max with my build.Past that would build an LSX.
Bigger engine has advantages in several areas. Makes more power on and off boost. Not just peak power and torque but it can have a much larger area under the curve .This is nice especially if you have gone to a bigger slower spooling turbo or turbos.
It can also spool up the turbo or turbos quicker. And as said you can make more power at a lower boost level than on the smaller engine.
Iron block 6.0 builds are pretty affordable. It does add think its actually about 80 pounds to the front of the car. A bmr type kmember setup and lighter a arms can help get that weight back down. But I did buy coil overs to let me raise my front end up as the combo of iron block and the weight of the turbo kit and heavy intercooler did sag down my front end even with the bmr kmember.
Bigger engine has advantages in several areas. Makes more power on and off boost. Not just peak power and torque but it can have a much larger area under the curve .This is nice especially if you have gone to a bigger slower spooling turbo or turbos.
It can also spool up the turbo or turbos quicker. And as said you can make more power at a lower boost level than on the smaller engine.
Iron block 6.0 builds are pretty affordable. It does add think its actually about 80 pounds to the front of the car. A bmr type kmember setup and lighter a arms can help get that weight back down. But I did buy coil overs to let me raise my front end up as the combo of iron block and the weight of the turbo kit and heavy intercooler did sag down my front end even with the bmr kmember.
06-23-2010, 09:55 AM
#10
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The beauty of the LS motors is that they are a lightweight all aluminum V8 that can make power to run with almost anything. I would never consider iron, it's "old school".
06-23-2010, 11:18 AM
#11
Personally I would keep your block. The hell with adding more weight to the car with an iron block. Look into ERL. You can ship them your block and they can re sleeve it and if you like, install billet doweled main caps. At a bare minimum I would have it re sleeved. The cost isn't that great for the added durability.
06-23-2010, 11:41 AM
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There was a guy in gmht mag that had a forged 347 and twin mp70s, on pump gas he made like 800 or so but on race gas and upping the boost he made 1004 rwhp so I'd say a forged ls1 would work fine...
Although it is for some reason Easter and cheaper to go a little bigger
Although it is for some reason Easter and cheaper to go a little bigger
06-23-2010, 03:09 PM
#14
i appreciate all the help fellas this site is by far my favorite. i am trying to keep weight down and maybe one day when the ls1 blows up ill go with that bigger cube iron block. maybe an lsx 454 twin turbo will fit the bill one day lol. when i want to make 1400 rwhp lol. again thanks, Justin
06-23-2010, 05:29 PM
#16
before the lsx block he had a 347 with twin 70's
aluminum will be fine fastest ls6 block went low 8's(y2khawk) pretty sure that was just rods pistons and good heads (no filler, no orings)
Iron blocks are cheap, but so are ls1/ls6 blocks if you are buying used.
aluminum will be fine fastest ls6 block went low 8's(y2khawk) pretty sure that was just rods pistons and good heads (no filler, no orings)
Iron blocks are cheap, but so are ls1/ls6 blocks if you are buying used.
06-23-2010, 07:18 PM
#20
As stated if you are going to build a motor..... spend a little more and get the 4.0 bore. You get a better selection of heads to run. Also an LS2 alum block can handle more power than an LS1 block. I've read a few times that with many street miles in the 750rwhp+ range the rings lose their seal. Pull the motor apart... hone the cylinders and then plop in new rings and you are good for a few more thousand miles until it will happen again. Guys went to the LS2 alum block at this point and problem vanished.
80lb weight savings costs about $600 more for an alum block vs. buying an iron 6.0 block for $300-400.
80lb weight savings costs about $600 more for an alum block vs. buying an iron 6.0 block for $300-400.