5.3 ls motor

fatstax · COBOURG, ONT

5.3 ls motor

slim · DUNDAS, ONT

If you wanted you could do a compression test . think it will be a hard sell unless you know it was replaced or you drop a 0 on it. but then you never know nothing surprizes me anymore priced low enough someone might want it for a few working bits and scrap the rest. I know Im no help.

DaveM · ONTARIO

It is an LS cousin. LM7 is the id code for that 5.3L truck engine. Iron block, aluminum head GenIII smallblock. Very good engines.

It is at least worth finding out what is wrong with it.

scott420p · BRAMPTON, ONT

From what I gather your motor would be considered part of the LS family(just an iron block instead). Here is a list of the engine models.
http://www.lsxp.net/#/the-ls-engine-family/4561249236

-- Edited by scott420p on Monday 15th of April 2013 02:30:15 PM

fatstax · COBOURG, ONT

so its not actually a LS motor. what is the difference? i might just save the heads and sell them at the flea market

Seeker1056 · DOURO, ONT

the 5.3 is an LS motor. Just happens to be in a truck so has different nomenclature.
with 480 on it - not worth much unless you can pedal it as a complete swap with pcm, harness etc
there is even a swap how to to use the truck underhood fuse block for a four wire hook up

MADSCI · NEWCASTLE, ONT

Everything form an LS1/6 will bolt directly onto your 5.3 ( 4.8 or 6.0 ) for that matter, the only thing you would ever have to do is drill and tap one hole in the side of the block if you ever decided to use an alternator mount from an 98 -2002 camaro......

DaveM · ONTARIO

It's still not an LS engine. biggrin

RPO codes are important and should not be scewed.

Hog · WOODSTOCK, ONT

It's a GEN 3 engine, the only difference between the LM7 and an LS1 is the displacement and block material. The LM7/L59 and teh LS1/6 share the same stroke, the LS1/6 having the larger bore.
Guys consider any GEN 3 engine as being in the "LS" family, this term should not be used. Either use the RPO or dont. Some guys used to call GEN 3 engines LSx engines, then GM camke out with their LSX series of crate engines which furthur muddled the situation. There are 5.3 L33 engines that are aluminum blocked as well.

Saying that the LM7 isnt worth anything because its "not an LS engine" isnt correct, but fine by me, cause it keeps GEN 3 LR4-4.8 and 5.3L LM7, L33, L59-flexfuel prices down.

The L33 uses the LS6 style heads, the only differnce being that the L33 heads(799) dont have the sodium fuilled valves that the LS6 heads(243) have.

The L33 5.3 uses flat top pistons and a cam with SLIGHTLY more lift than the 5.3 LM7, and is rated at 310hp/335 lb/ft torque. The standard LM7 5.3 is rated at 295hp/335lb/ft torque, although back in 2000 the LM7 was rated at 285hp/330lb/ft. 1999 5.3 LM7's were rated at 270hp/315 lb/ft.
The GEN 1E 1996-2002 L31 Vortec 350's were rated at 255hp@4600rpm/330 lb/ft 2800rpm.

The 1998-2000 LS1 was rated at 305hp@5200rpm/335lb/ft torque@4000rpm, the 2001-2002 LS1's got the higher flowing LS6 intake manifold and slightly smaller camshaft and was rated at 310hp@5200rpm/340lb/ft@4000rpm. Although many LS1 manual trans cars regularly chjassis dyno at 300rwhp or more. Chev under-rated these LS1 F-bodies so they didnt crowd the LS1 powered 345hp-350hp Corvettes. These F-body LS1's probably output around 360 hp at the crank.

The 1999-2000 LQ4 in the 3/4 ton trucks was rated at 300hp@4800rpm and 355 lb/ft@4000rpm torque.
2001 LQ4 was rated at 300hp/360 lb/ft torque from the HD trucks with teh 4l80e trans, and 320hp@5000rpm/370lb/ft@4000rpm in the AWD Sierra C3 trucks/1/2 ton Suburban with the 4l60eHD trans.
2002 introduced the GEN 3 LQ9 rated at 345hp@5200/380lb/ft torque!4000rpm in the Cadillac Escalade/EXT and later in the 2004 B4V Performance PAckage 2wd VHO Texas Truck 1/2 ton extended cab trucks witheth 4l65e trans. Only 512 of these 2wd Lq9 6.0 trucks were built. LQ9 6.0 also came in the 2004 AWD SS Silverado pickup truck.

To round out the GEN 3 family was the 2001 LS6 rated at 385hp @ 6000rpm/385lb/ft@4800rpm. Cam, 243 heads with sodium filled exhaust valves, differnt cam, high flow exhaust gave the LS6 the exytra output over the LS1.
In 2002-2004 the LS6 was rated at 405hp@6000rpm/400lb/ftt orque@4800rpm with a 6600rpm fuel shut-off. These LS6 powered ZO6 hardtop Corvettes can run high 11's in the 1/4 in ideal conditions bone stock.

2003 there is an aluminum 5.3 alluminum block/heads usd in the SSR RPO LM4 and is rated at 300hp@5200rpm/331lb/ft@4000rpm, these were also used in Trailblazer EXT's, Avalanches, Rainers but with a 290-295hp/320-325 lb/ft torque rating.
In 2004 the SSR got the 6.0 LS2 with its aluminum block/heads and is rated at 390hp@5400rpm/405lb/ft torque@4400rpm.

GEN 3 engine info.
http://www.enginebuildermag.com/Article/1096/gen_iii_gm_small_block.aspx

Any GEN-III engine can provide lotsa power, with decent fuel mileage as well.