V8ImpSS

I made a post about 2 weeks back asking for the max bore possible on the stock sleeves in an LS4, the FWD 5.3L V8. Id appreciate any help I can get! And I mean c'mon enough already with not counting the LS4 cars as real GM muscle, if you were going to have a FWD car wouldn't you want it to have the latest small block Chevy?

NemeSS

iTrader: (127)

I would say possibly .010-.015 max from hone.
Is the motor damaged? Or just looking for more hp?
Remote mount turbo is what i would go for if i owned one of those cars and looking for more hp.

Tainted

iTrader: (9)

Well actually no, id save my pennies and get the RWD v8. Not the wrong wheel drive truck v8 :p

No idea on max bore though. If you're going that far you might as well just get a short block

V8ImpSS

no damage, always in the pursuit of more power!

There is a turbo kit that promises 505 fwhp, up from 303 at the flywheel...but its 5 grand and thats WAY too much power for a wrong wheel drive street car.

I also looked into an STS universal kit, but again no thanks...

I have an engine shop that owes me a free build...so my plan was to bore out to LS1/6 spec and essentially have an LS6 (LS4's have 243 heads) throw a cam at it and be done with 450 hp easy...but then I come to find that the LS4 cannot be bored out the same as the truck 5.3's, which based on your knowledge is confirmed...looks like I'll be resleeving

I don't wanna have a custom crank made to get extra inches, just wanna bore...what's the biggest I can go as far as bore and displacment? can I go as big as 4.125 to give me 387ci? (resleeved) will that require new rods too?

big thanks to NemeSS for being first to help the less respected of the current SBC community

V8ImpSS

the LS4's have a shortened crank and block, plus a super low profile accessory drive...so replacing it with a different LS based engine is out of the cards period, simply just won't fit its too wide, er well long...whatever

there's nowhere to buy an already built short block from either, has to be my engine unless I wanna buy a core which I don't, but that's not an issue because my trans is about to shatter anyways, and it's getting a newer model 6T75 all beefed up regardless of how far I go beyond a cam with this engine...really want more cubes

bww3588

iTrader: (49)

I highly doubt the sleeves are thick enough to bore .119 to ls1 specs. I would put money on a .010 max hone.

Kaane

iTrader: (2)

It's pointless to bore a sleeved motor, there is not enough material to make any gains. If you want more displacement, you will need to resleeve it.

DavidGXP

iTrader: (14)

How much power do you plan to make? Im around 450 (crank) 370fwhp with cam, ported heads/intake, 10.5 cr and headers. You can use the tfs 5.3 head and cam package with a ls6 intake and headers. There was a member who made 495 crank hp with the tfs heads 222* tfs cam with the mods listed above. This was dyno'd with open headers and electric water pump only. (max effort run)

If the shop owes you a build then have them sonic test the bores to see how far you can go. GM sells .5mm over sized pistons. Trw sells pistons that are much bigger.

My cars power is very hard to control without the anti score kicking in and killing power.

DavidGXP

iTrader: (14)

You could always use a 6.0l block with the ls4 crank and accessories. You would need to use an adapter plate on the bellhousing. I would have the bellhousing milled down and weld on the adapter plate.

autodoctor911

I don't think 5 mm is possible, but .5mm or .020" should not be a problem. I think the sleeves in a 5.3 are thicker than 5.7 though, possibly even the same od as 5.7. have not confirmed this, but I do see schwanke sells a short block based on L33 aluminum block with 5.7L piston size.

I am wondering if that is a maximum bore point to fit the stock 3.898s or can you go to the 3.903 or 3.910 with these sleeves. with a sonic test to make sure they're centered of course, cause a cast in sleeve could definitely be shifted. I would like to know if the 5.3 aluminum castings use the same molds as 5.7s. If so, a 4.2 sleeve is an option.

NemeSS

iTrader: (127)

He's gonna spend way more on a built sleeved ls4 regardless if shop owes him. Than 5000$.
Build a remote mount diy turbo system. No need for sts. Source all the parts yourself. Save cash by installing fabricating by self.
Upgrade fuel system, tune. More Hp than will ever be able to use.
The h/c guy mentioned his car hard to control with so much power. Turbo will make more.

Robofuzz

Why don't you sell the car and buy a used G8?

V8ImpSS

I know your just about the fastest N/A LS4 on here, and if you say your car is hard to control making 450, which is totally believable, then I think I'm just gonna go with a similar build to yours and I'll be pretty happy with the gain for the $...thanks for the insight

really? I wouldn't even have to mess with the adapting anything because I'm planning on going with the 6T75 trans anyway...but I thought the LS4 block was shortened as well to accomodate the shorter crank so I don't see how this would work...I hope I'm wrong on that then I'd have 364ci and make 500 horse with ease!

all I want is to be able to take a stock RWD LS or Hemi powered car on the highway...I already kill 4.6 mustangs

I don't have the time to deal with something like that anymore, I don't wanna mess with a turbo on this car, just simply not what I want

If I had a dollar for everytime someone said that to me I could go buy a G8 and pay cash.

but believe it or not I own this car because I like it...imagine that...plus I already have other RWD cars to play with and pontiacs are ugly

V8ImpSS

Say I resleeved the motor...what's the biggest bore I can go? Could I do 4.125 like an LS7 to give me 387ci with the stock crank. Does that much of an overbore require different rods? Would stock LS7 pistons work?

Or if I wanted to swap out the block, could I use an LS3 then put the LS4 rotating assembly in it? Or is the LS2 my only option?

racer7088

Most aluminum 4.8/5.3s and irons can be bored to 3.900 actually. The other larger bore blocks (5.7/6.0/6.2/7.0) can't be bored that much over but most 4.8/5.3s can. We have done about 30 in the last several years all with no problems. They have a way thicker liner or another words are like a 5.7 with a way thicker sleeve that is only bored out to 3.780. If you have the heads off you can see this pretty easily. All the Aluminum 4.8/5.3 blocks we have seen are like this. We have one here now and it's like this as well.

Tainted

iTrader: (9)

I know someone with a bland *** impala aint calling a G8 ugly

V8ImpSS

My impala is far from bland...and all pontiacs are ugly except pre 1971 GTOs...if your not in here to commend on the question then GTFO so sick of the haters on here

CoolAid

DavidGXP

iTrader: (14)

The ls4 block is not shorter. I wouldnt bother with sleeving. Do a rear mount turbo, or stab in a cam with a LS6 intake.
You can PM me for details to aviod negitive comments. You gotta take back the ugly Pontiac comment though... Lol

This car should trap 114-115 this year, and Im hoping for 1.8 60ft times (fingers crossed!) 3865 lb race weight and all motor!
Shifts are set at 6800 with 3.69 gears and 3500 stall.

Ellsworth