CodyBoy

2000 Silverado Z71 with a 5.3.

So what LS is this? Then I see some posts that have LQ.

I am rebuilding my engine due to lack of oil pressure "read zero".

And the last engine I have had any rebuilding experience with were the old 350's and a 396 big block.

So not sure what engine I even have.

Thanks.

parks450

iTrader: (17)

You have a LS based engine Gen 3

CodyBoy

OK but what about the #s

LS1 LS2 LS3 etc?

Thanks

01ssreda4

iTrader: (96)

Its not an LS anything. Its a Gen 3 5.3.

LR4 4800 4,807 cc (4.807 L; 293.3 cu in)[11]
L33 5300 5,328 cc (5.328 L; 325.1 cu in)[12]
LM7 5300 5,328 cc (5.328 L; 325.1 cu in)[13]
LM4 5300 5,328 cc (5.328 L; 325.1 cu in)
L59 5300 5,328 cc (5.328 L; 325.1 cu in)[13]
LQ4 6000 5,964 cc (5.964 L; 363.9 cu in)[14]
LQ9 HO 6000 5,964 cc (5.964 L; 363.9 cu in)[15

parks450

iTrader: (17)

You have the lm7

WS6tx

iTrader: (25)

Agreed ^^^^ LM7

remauto1187

iTrader: (1)

The LM7 which is the RPO code for Gen 3 5.3L truck engines are the most common truck engines and they are iron block with aluminum cylinder heads. The LM7 and all 5.3L truck engines are more or less a LS1 externally. The big difference is the smaller bore of the 5.3L. A 5.3L can be bored to the LS1 STD size of 3.898". The heads of the 5.3L have smaller combustion chambers than the LS1 typical heads (243, 799, etc.). The heads are swappable. There are some differences starting around 2005 which is when the Gen 4 engines came about. There are Gen 4 5.3L engines and their most notable differences are the computer (PCM) that control them and the location of the camshaft position sensor. All Gen 3 and 4 engines have aluminum heads. There are iron and aluminum versions of the block for all version of 4.8, 5.3 and 6.0L engines. Then there are even more differences when you get into the Variable valve timing (VVT) blocks. There are quite a few books out that get into all the differences and do's and dont's. Great info and quite interesting.

Have a look at this breakdown: http://en.wikipedia.org/wiki/GM_Vortec_engine

CodyBoy

According to Wiki I have a 4.8 that is stroked by 9mm.

So the bore is the same as a 4.8?

01ssreda4

iTrader: (96)

I really never understood why anyone compares everything to an LS. They are all Gen 3 engines, not LS based engines. I guess because the LS is the most known letter designation but that doesn't make it any less silly.

bww3588

iTrader: (49)

or because the LS1 was the first GEN III engine, so technically all subsequent engines are based off of the LS1.

remauto1187

iTrader: (1)

HOLY COW WOW!


What is the 8th letter/number of your VIN code.

4.8L and 5.3L have the same bore but different stroke.

4.8L Stroke 3.27"
5.3L Stroke 3.622"

3.78" Bore both.

CodyBoy

8th digit is a T

So according to Wiki it is a LM7

remauto1187

iTrader: (1)

Yep its a LM7.

Ive got 2 of them in my garage right now that i picked up from a salvage yard. A 2002 and 2004 model. They can be bored to the 5.7L LS1 specs. One is going into my 85 corvette and the other is going into my 99 GMC Sierra (5.7L vortec equipped currently). I am lazy and no longer wish to mess around with a distributor cap and rotor ....not to mention all of the performance parts available for the Gen 3 engines. My Vortec 5.7L is tired with 240K on the clock. Not worth the money to get it rebuilt or a reman when i take a LM7 and bore it and end up with alot more HP than i would with 5.7L vortec and still run on pump gas.

Its a win win for me.

Got my (2) LM7's for $350 for the pair too!