Gettyhumper

I'm considering going to an LS 2 for a supercharged build. If I buy a new block from GM can I expect the bore dimensions and finish to be accurate enough to just install a forged rotating assembly ( assuming the rotating assembly is accurately machined)? I'm on a budget and trying to save some bucks by buying a block and installing the rotating assembly my self. I have the measuring tools and the experience to measure the clearances, file fit rings, check piston to bore, etc.

Anyone one done this? What's your opinion?

LLLosingit

iTrader: (4)

It's better to have a machine shop setup the bore for the pistons that are going in. You're not likely to get a match by buying a new block and new pistons.
If you're going to spend the money on a forged rotating assembly then you might as well have the block professionally prepped and fitted for pistons so that it will make the desired power level and live as long as life as possible.

Senna

iTrader: (1)

I wouldn't assume anything.

I bought a new LS3 block and it was pretty much spot on for main bores, deck height and cylinder bores.

It will matter what pistons you use. some pistons (I think Diamond) call for a finished bore size such as 4.000" and some call for piston to wall clearance such as .003" that can be .0005" or more over factory.

Also, factory is not finish honed with a torque plate.

pantera_efi

iTrader: (1)

Hi Humper, I have bought LS-3 "unfinished" bore (3.96") Blems from GM dealers @ under $1K.
You need to ask your local parts counter man to find one.

Lance

Gettyhumper

But the blems could be anything, right? This might even be something that requires corrective machining - right?

bbond105

Right

pantera_efi

iTrader: (1)

Hi Humper, some of the reported "tech" here is from a type of person who would believe are not trustworthy.
The cost of a LS-3 block from a GM dealer is about $1250.00. (new)
The cost of a "blem" may be lower AND the few I have purchased were WITHOUT a found mark in a area of concern.

BOTH are sold be a GM dealer with the absolute ability of a return if not satisfied with the product. (state law & GM law)

I agree with Senna, get a block, hone to .00+", find/order a piston set : +.003"-.005" O/S is VERY COMMON.

I can supply a piston/ring set of the correct size AND NO EXTRA COST for a O/S bore.
The File Fit rings will require less work when the bore is O/S.

Lance

Gettyhumper

I've searched for the last month and have not found an Ls3 block for that price. LS2 yes, but not LS3. LS2's are about $1150 on all the sites I've found. I live in a very rural area and the local ,Chevy dealer has not heard of the blem blocks.

Could you give me links to the $1250 LS3's and the blem block?

pantera_efi

iTrader: (1)

Hi Humper, understand I buy from Guaranty Chevrolet at wholesale.
I can do this type of purchase at most GM dealers.
So I ask you location ?

Lance

Gettyhumper

I'm in East Tennessee. Largest cities around me are Kingsport and Morristown (1/2 hour away) and Knoxville (1hour away). I'm in Rogersville, TN. A few dealers are:
Rusty Wallace Cadillac GMC Morristown, TN
Courtesy CHEVROLET BUICK GMC Kingsport, TN
Beaty Chevrolet, Knoxville, TN
Reeder Chevrolet Knoxville, TN ( Home of the East Tennessee Corvette Club )

07NBSChevy

iTrader: (1)

I have seen 2 new LS3 Blocks, #12623967, on ebay for $1380 over the last month or so. I ended up getting one and with free shipping as well. Most sites sell them for $1,500.

I have also seen new LS2 blocks, #12602691, sell for $999.00 on ebay with free shipping.

As mentioned, I would always have the bore checked with the pistons you will be using to be on the safe side.
I have never ran into a new GM block that has been out of spec, but better safe than sorry.

CAMSTER

iTrader: (10)

For boost I'll stay away from the ls2 for sure ls3 is a stronger block but I would go with LQ9 or an LQ4 these are cast iron blocks and much stronger for boosted aps.

Gettyhumper

I'm the OP. As I said a few posts up this thread , this is going into a C5 vette. I won't use iron for handling reasons. I know it's stronger but I will stick with Aluminum.
Thanks.

Patron

Getty your wanting a new block correct? So around 1200 bucks for a Factory block with cast iron sleeves. Your looking for a good deal and don't wanna use a iron block. Ok here's the end to your problem.

1st finding a good 4.00 inch aluminum block will be something in itself. 5.3's maybe but Ls3 or 2's are hard 2 find.

2nd you have 1200 add 800 and get a dry sleeve block 4.185 max bore. $2k. TSP.

3rd you need some local guys who buy scrap or used blocks or salvage yard make some calls and make some friends. Once it's in they'll give you a call because everyone likes $. You may have to wait to find a good 1. 6.2 Ls3 block goes for around 600 from my guys. Only 1 problem there not coming in like old everyone wants them. Friends call friends before the public gets notified. If all else fails you gotta pay the man. Thought of getting one myself but couldn't find a good core for a good price for a resleeve in the future.


TuskeyZ you find me a aluminum 5.3 for $300. Like you did. lol.

gnx7

iTrader: (28)

Summit has LS2 blocks new for $1133 delivered. Hard to beat.

We bought a few blem blocks and while most where useable.... a couple had gaps around the sleeves on the deck itself. Worthless paperweight. Such a hassle to ship back (we paid shipping cost).

Just buy this and do what you want with it
https://ls1tech.com/forums/parts-cla...g-harness.html

G Atsma

It turns out gaps between the sleeve and block are normal. Does not happen all the time, but if it does, no big deal. The block is cast around the sleeve, and once in a while you get a void or two.