z28adiction

iTrader: (1)

Just throwing the idea around. i know lifting heads has been the biggest problem when talking FI and high boost. My setup will consist of (2) 1.06 35rs and im looking for 900 hp in high boost. Im looking to go no higher than 20 pounds to achieve this goal, and since i know 20 psi is getting up there was just wondering if the extra cost on an lsx block and the extra number of studs would be worth it over an lq9 as to not to lift a head, im not looking for big cubes, still just looking for a 408, but just looking at more "reliability" as if that word can even be used when talking about a car with that much hp. lol

elias_799

iTrader: (8)

if you want to be reliable go with the lsx. and if you go with the lsx you have allot more potential (up to 2500hp) in it as long as everything else can handle the power. the lq9 will defiantly lift the heads at 20 psi, it is just a matter of time. good luck.

z28adiction

iTrader: (1)

thanks for your input. and i figured i would, to me the lsx is definately worth the extra coin. has anyone lifted a head on an lsx block at 20 pounds before?

trans2000am

iTrader: (49)

with 6 bolt setup i doubt it. unless the were installed wrong or tuning issue. 20 pounds on a 6bolt setup should be cake

z28adiction

iTrader: (1)

that what i like to hear. overkill in some situations equals reliability i guess.

ls1290

iTrader: (20)

No guessing about it. Pure facts

MY99TAWS6

iTrader: (3)

I have seen quite a few iron block engines with decent thick deck heads like AFR or Trick flo go to 20psi no problems at all and handle mid 1000 engine hp levels. You can search under "boosted lists" they used to be sticky in this forum but still seem to come up with search. The lsx is pretty new kid on block and many guys were making big power with the 6.0 iron block from many years no problem. Past 20psi then sure go lsx but some say lifting the heads is more tuning then anything else. Keep timing conversative and no big problems.So not so much boost as cylinder pressures.

LSX is overkill unless shooting for closer to 2000 and above hp and unless you want a 427 or 44x ish size of motor. I can tell you from experience that its hard to hook much over 600 rwhp on the street even running drag radials 24/7. Our f body cars have lousy traction control and no active handling. I am looking to try a racelogic variable traction control out possibly on my car. I find a 408 plenty with boost on the street. And not even running past 7.5 psi right now. Was thinking shouldn't have to run much past 12 to 15psi on my setup to have way more power than I can hope to use but woudlnt' be afraid to go to 20psi very rarely. I see no reason to have to go to 20psi regularly with my setup.

Shawn @ VA Speed

iTrader: (3)

just tore apart Fireball's motor-stock ls2 block etp 4 bolt heads gm head gaskets,over 40 passes at 23+ lbs boost,no head gasket issues.
It all comes down to proper parts selection,proper assembly and proper tuning.If the engine is happy it'll stay together.

Fireball

iTrader: (21)

don't forget the GM main bearings

LS6427

iTrader: (2)

LSX block is great for anything over 1,000. Yeah, people are running over 1,000 RWHP with aluminum blocks and 4 cyl-bolt iron blocks, but why be on the edge all the time. For the tiny bit of weight increase, why not have double the reliability. And its cheaper than a resleeved aluminum block.

qqwqeqwrqwqtq

At 1000+rwhp I prefer the 6-bolt setup. LSX or Warhawk. We've built many iron block combinations living with more power than that but I think the extra fasteners go a long way towards long term head gasket reliability.

It may be overkill but I'm ok with that.

Shawn- Fireball mentioned in his thread there was some evidence of leakage into the water jackets. Not saying it's the end of the world to push some water but a 6-bolt setup would probably eliminate the problem entirely. Do you agree?

Shawn @ VA Speed

iTrader: (3)

Absolutely the 6 bolt setup would have helped,most of that if not all of that came from a hail mary pass at the end of the season.This engine also made over 1200rwhp with a glide.
The original question was for a 900hp setup,at 900hp 4bolt heads will work fine.
There are always better and more expensive parts,while the 6 bolt would be better,it's doesnt have to be used,just like a billet crank would be better,but doesnt have to be used.All these more expensive parts do is increase the margin for error.

brobards

iTrader: (1)

Will a better headstud increase the boost threshold before you begin pushing water?

A 7/16" L19 headstuds has an equialent clamping force as a 1/2" ARP headstud... How many have tried these and with what results?

How large of a headstud can you run on the iron block? I thought Paul Major was running 9/16" on his LSX.

How much will o-ringing the heads improve the boost threshold?

What would the guys making power with a production block (fireball, shawn, etc) recommend to make the 4bolt heads work?

Shawn @ VA Speed

iTrader: (3)

the stud itself is not usually the problem

1-thick deck cyl heads-most important
2-properly machined surfaces-depending who does this,it might not be flat enough-alot of surfacers actually put a slight dish in the surface.
3-properly yielded fasteners-arp torque specs arent it
4-correct combination of parts-wrong parts creat alot of extra cylinder pressure
5-proper tuning
after that you can do thing like 1/2 studs
i have double oringed several engines-works really well,in 7 years of running this setup on my turbo sbc that has made anywhere from 1800-2500 hp and never any head gasket issues

z28adiction

iTrader: (1)

at this point im going to just spend the extra money to go lsx. its worth the added insurance and when you totally build a car from the ground up like i want to do the extra 1600 or so for not having head lifting problems is worth it.

But is it worth it to have an lsx block and heads o-ringed or is that just way overkill for around 900 to a 1000-

redss86

I am a virgin when it comes to boosting, and don't know much about it so take this for what it's worth.

It seems you are very concerned with added insurance, when it comes to your engine handling your power goals. Correct? If so, then from what I have read/learned on here, there is really no such thing as overkill when it comes to building a STOUT core (long block). Yes, 6 bolt heads, and O-ring on top of that does seem extreme, but if it's possible do it.

Just my .02, (and that isn't much)
Joe

Pro Stock John

iTrader: (34)

I'd go LSX if you really want to run 8's OR you want piece of mind AND you don't mind spending another $2000 to machine the LSX block to a point where it's ready to go. 6 bolt TFS heads don't cost much more than 4 bolt heads so it's really going to come down to the additional cost of maching the LSX block (or going to an ERL block).

You can go mid 9's with less than 900hp, I went 9.40 back in 2006 with 680rwhp and my blower setup. 900 crank hp should be good for high 8's with some work.

Fireball and Mark Koehler's cars both went low 8's in 2008 with 4 bolt setups, I believe Mark pushed water here and there but I'm not sure if how many times if any he had the heads off.

LASTLS1

iTrader: (7)

Trust me, it will be money well spent. This is comming from a guy who's replaced alot of head gaskets. It's not worth the cost savings, unless you like changing gaskets. I would spend double for the LSX!

mdbreaux

LSX. I eventually lifted the heads by pulling 2 head stud threads out of the block on an LQ9.

barnat

iTrader: (59)

LOL Heres the thing my man! An iron block will be good to 900HP and above My LQ9 APS is only tunned to 9 PSI and im allready at 800 engine HP with no problems at all and i know i can push it way further and safly with no problem if i wanted to in the future.
Heres the thing ,,,,If you've got the money to burn and want the LSX and bragging rights, Buy the LSX! If moneys alittle tight and by buying the LSX block your going to skimp elsewhere on your engine build to make up for it? Go with a iron block. Either way, stay iron if your goals are 900HPor above!