LM4 5.3 truck vs LM7 5.3 truck

[leochevy2001]

Why does the 03 LM7 5.3 have 10 more hp than the 00-02 and 5 more hp than the LM4 5.3? What all was changed from 00-02 to 03? Why would GM make two 2003 5.3L motors and have one with more hp than the other and the same amount of torque? How do you know that you are getting a LM4 or LM7?

[farmtruc]

not sure, but the tuning is a tad different , not much , but it is different, that may take care of the 10extra hp


maybe someone else will chime in.


later,

allen

[Hit Man X]

Originally posted by leochevy2001@Sep 11 2003, 11:32 AM
Why does the 03 LM7 5.3 have 10 more hp than the 00-02 and 5 more hp than the LM4 5.3? What all was changed from 00-02 to 03? Why would GM make two 2003 5.3L motors and have one with more hp than the other and the same amount of torque? How do you know that you are getting a LM4 or LM7?

99 had 270hp
00 had 285hp
01 had 285hp
02 had 285hp
03 had 285hp
04 had 290hp I think

99 had a different cam than the 00-02's.

The '03 probably have a different cam again or a few degrees of timing added.

GM is stupid. Just get any used 5.3 and throw a 6.0 cam in there...you can get it probably for free and will make about 20 more hp than a 99 and about another 10 than the 00-03

[farmtruc]

hey, Hit man, that's a good idea on the 6L cam, i may be able to swing something for my f-n-law, he's on a real tight budget but wants some extra power,

thanks,

allen

[99 red silver]

I guess next mod for me will be head and cam. Not for awhile need to save up some money and pay for last mods.

[Hit Man X]

Originally posted by farmtruc@Sep 26 2003, 08:52 PM
hey, Hit man, that's a good idea on the 6L cam, i may be able to swing something for my f-n-law, he's on a real tight budget but wants some extra power,

thanks,

allen

01+ 6.0 cam: 196/207 467/.479 116

99 5.3 cam: 191/190 .457/.466 115.5
00+ 5.3 cam: 191/190 .457/.466 114

LS1 C5 stockers:

1997-1999 199.207 .475/.479 117
2000 198/209 .500/.500 115.5
2001+ 196/207 .467/.479 116

LS1 F-bod stockers:

1998-2000 LS1....198/209 .500/.500 119.5
2001-2002 LS1....196/207 .467/.479 116

I'd look for the most duration and a tigher LSA for the most power...gains will be 10-15 tops...but it will be noticable.

[99 red silver]

Question why does my Ls1edit show a l7 instead of a 4 when I own a 99 5.3L. ?

[farmtruc]

not sure, but you have a lm7 i guess, don't know.

[droppedgmc]

http://www.jcscoops.com/performance/...gine_specs.php
here lm4 specs from the trailblazer
http://media.gm.com/division/2004_prodinfo...azer/specs.html
i think this was the first 5.3 (99&#39
http://media.gm.com/corpcom/98news/p980105b.htm
after searching more lm4/lm7/l59
http://www.gm.com/automotive/gmpowertrain/...ehicle/5300.htm