bassprokd

Hello all...new to the board. Back in the drivers seat behind my new (to me) 02 Z28 M6 after selling my 02 WS6 CETA last year (A4). I'm ready to start an engine build as the Z28 I bought with intentions of building a motor since it has high mileage and an oil leak (rear main seal probably). Anyways, I've been reading a couple books I purchased on building LS motors and what caught my eye is the ability to install Darton Sleeves in the LS1 and stroke it to a 468ci using a 4.185" bore on the darton MID sleeves and 4.25" stroke. Now this will not be a DD but more of a weekend warrior for street/strip use. This seems to be a very rare setup. Does anybody have any experience with this setup or is there a reason that nobody does this? I'm looking for some HP estimates with a good head/cam package on pump gas. Will this not be a reliable setup due to the rod angle creating excessive cylinder wall wear? Any thoughts or input would be great! (Upgraded Tranny, rear and suspension will be addressed with this setup later).

red fury

iTrader: (1)

Cool idea, I hope some legit people reply with some facts! Most will say do not waste your money on the sleeved LS1, buy the LSX block.

Anyway, a good read is in the April 2007 GM High-Tech mag. 455ci resleeved LS1, page 12

evo2ls1

iTrader: (2)

Agreed, sounds like it would make big power, I have been wondering what all can be done if you have a ls1 and want bigger cubes

Grimes

iTrader: (3)

Most guys here will tell you that for street use, you'll get better longevity keeping the stroke to 4" max. You should call up some of the sponsors to get a better idea of the cost. You'll need some major cash for the supporting mods, like FAST intake, killer exhaust, etc.

LS6427

iTrader: (2)

My builder just finished a 468ci with the new sleeves and the RHS block. It was built to road race only. It'll get rebuilt soon regardless......they run those things hard....

If you want it to last a long time......do a 4.185 bore x 4.125 stroke. 454ci. All else being equal, you'll have about 25 HP less. If you ever plan to spray it, go with a 4.155 bore = 434ci.

Depending on what heads, intake, TB you go with....it'll make an easy 650 RWHP on pump gas with the right cam.

You'll need to spend $8,000 on just heads, intake and TB to get the MOST out of it.....

4L60E will blow up on your first hard run.....lol So you'll need a 4L80E to hold that power for more than a week.

Get A 12 bolt rear-end too....because the stock rear will explode as soon as you just put that thing in gear....lol

You'll need a host of suspension parts too.....maybe $1,500-$2,000 worth.

.

PREDATOR-Z

Get in touch with Tony Mamo at AFR.

RAMPANT

iTrader: (17)

Not sure that 650 rwhp easy is a very reliable statement on pump gas, unless you mean E85 then there might be a better chance of it.

I only expect 600 and a little more with my set up at the wheels.

If it had been available at the time I would have gone with the ERL Superdeck 6 bolt and do a 454. I currently have the REDs LS7 sleeved block, bored to 4.198", yep nothing left to bore over in those. I like the idea of 100lb reduction off the front wheels though. It is not easy to pull 100lbs out of these cars. I went for a stealth approach on mine that would meet local emission laws. It idles at 700rpm with next to no lope. I have OBDII cats as well. I still have catherdral port heads though which hurt it a little, but they are one of the best cathedrals out there. Mast 275s. A ported Harrop 55mm for the idle.

For the street I would keep it to 4.125" stroke as well. If you go down to 440ci you can go with a stock LS7 block and it has the longer sleeves, but does not have the 6 bolts for the better heads.

Heads for the project will cost a pretty penny and you are likely best off with Mast or WCH LS7 based heads to get the most from it, with a Fast 102 intake.

I would never recommend a 12 bolt on a M6 car at these power levels, 450 rwhp tops, trust me I know. I broke mine 4 times with 520. I have a MWC 9" now. In an auto, no problem, you could make another 200 hp and be fine with a 12 bolt. M6s are just to harsh a shock with a tire on it.

Good luck.

bassprokd

Lots of good input guys...thanks! The 454 with a 4.125" stroke is a good recommendation to keep it reliable. Super chevy did an article on the 468 build. They were at 12.25:1 compression and got 737hp with bAse ls7 aftermarket heads. Of course this was not on pump gas. It was done on dyno I am pretty sure but this may be crank hp.

bassprokd

Not on dyno so def crank hp but here is the article
http://http://www.superchevy.com/technical/engines_drivetrain/completebuilds_testing/sucp_1110_ls7_stroker_build_the_power_of_7/
Forgot that they also through a 200 shot of nos to it and made over 1000hp (crank).

N2OBaby

Killer thread here.

I would eventually like to build a 434 CID LS1 or LS2 or a 436 CID LS3.