GrnDragon

iTrader: (4)

I know many have said that the LS7 block isn't going to hold much power (like 800+ RWHP) very reliably under boost. Has anyone actually hit the limit for a stock LS7 block, mainly the sleeves? If so how much HP was it making? If they cannot hold the power I'm just out of options other than waiting for the Warhawk, seeing that it costs about the same as resleeving and bulking up a stock block.

edwardswb

iTrader: (6)

I'm waiting for the Warhawk man. There's no sense, in my opinion, in risking it with an LS7

coop5885

iTrader: (2)

Gmpp???

chuntington101

Jeff Schwartz is buliding some pretty insane LS7s at the min. thinks he is upto about 1200rwhp going in a 2200lbs mid engined car. should befun! lol

http://www.schwartzperformance.com/alien.htm

thanks Chris.

ChaseSS

iTrader: (17)

that is absolutely, sickly, digustingly, ridiculously insane

1dirtyZ

iTrader: (1)

has anyone actually had problems with a boosted ls7?

chuntington101

there where stories of ProCharger destroying customers cars and then walking away form them, but i think they where just stories.

you have thought the blocks could tkae as muchas the LS2 and they are going over 1000wrhp in some forms. also if you bust a sleve you can get them swapped for the MID (i think) ones now!!

thanks Chris.

GrnDragon

iTrader: (4)

All this is why I cannot decide which is the best choice for a block based on strength and cost for about 800-850 RWHP on pump gas and street tires (the car will see little track use).
-402 LS2
-427 LS7 [about $1000 more than LS2]
-427 resleeved LS2 (with stock mains) [about the same cost as an LS7 block]
-427 Warhawk [about $2000 more than LS2]

11 Bravo

iTrader: (3)

I'd go with a Darton MID sleeve LS1 or 2 block.

Steve - Race Eng

iTrader: (1)

I repaired three LS7 blocks, and a C5R block with cracked liners recently. I have two more cracked sleeve LS7 blocks on the way in.

They crack right below the flange. The C5R sleeve came apart there and was sitting on the main web. The sleeve flange was still in place.

I know one of the LS7 blocks was boosted. All the other blocks were NA including the C5R.

Most blocks can be repaired using the Darton LS7 dry liner. These liners are approximately three times stronger than the original liner and will go to 4.185" NA. I repaired all the above blocks using the dry liner.

An LS2 block or LS7 block resleeved with Darton dry liners is plenty strong and much less expensive than an after market block.

Darton now has MID sleeves for the LS2 LS7 blocks. One part number covers the range from 4.125" to 4.200". I am finishing up an LS2 MID today for a boosted street engine. Waiting on two more sets for LS7 blocks I have sitting here with broken wall castings.

The L92 block is problematic. The installed sleeves have roughly .100" wall thickness. If you can find a good block with sleeves on center and straight up and down, you can bore it to 4.125" for NA use. I just repaired an L92 with Darton LS7 dry liners. Barely was able to get the aluminum bores to clean up because the original cast in liner in #7 hole was tilted over to the side. Some of these L92 blocks won't be repairable because of the sleeve placement, tilt issue.

Steve

Steve

xfactor_pitbulls

iTrader: (16)

Good info Steve. Thanks for that.

GrnDragon

iTrader: (4)

Thanks for all the information Steve! I feel the resleeved LS2 block should be fine for my application, but then my concerns go to the stock main strength (the only way this is a cheaper is if the stock mains are strong enough and billet mains aren't necessary) and the 4-bolt heads. I've read about boosted engines "pushing" water on a regular basis and it sounds like the only solution to this is the 6-bolt heads. I just don't know if 12-15psi on a 427ci LSx engine producing about 800-850 RWHP is enough to warrant the extra expense of the Warhawk stuff.
On the flip side of the coin the added expense for the Warhawk stuff is only about $1000 more, and in the total cost of the engine that is less than a 5% increase in cost for a MUCH stronger engine... I really wish someone would get some results/extended testing on the Warhawk stuff!!!!

Stang's Bane

iTrader: (22)

I guess the question here is how much do you want to overbuild. At 12-15 psi you SHOULD not have any problems pushing water.
Of course the warhawk/LSX stuff will be stronger/more expensive, but do you need it??
There have been lots of cars in that power range that ran fine on 4 bolt heads and stock type blocks.

corvettetimmy

I did a re-sleeved ls2 block and made almost 800 rwtq and 750 rwhp. I will let you know how it holds together once i find my other 5psi of boost...

Wide Open

Vette magazine just did an article on a STS LS7. Boost was limited to about 6psi due to the high stock compression ratio. The shop that installed the turbo system thought the block would hold 12psi if forged internals with lower compression were used.
http://www.vetteweb.com/features/vem...kit/index.html