Many consier the 5.7L LS1 as "the new 350 Chevy", but that title more accurately goes to the 5.3L Vortec truck motor. As the bread and butter small block from 99 onwards, GM installs the 5.3L in the vast majority of its fullsize trucks and SUVs. Considering that GM has build way more trucks than cars in the last 10 years, the 5.3L is far more plentiful and cheaper than its 5.7, 6.0, and 7.0 liter big brothers.

For roughly $500 at your local boneyard, complete 5.3L motors can be had for a fraction of the price of an LS1 or an LS6. Price alone, however, isn't what makes the 5.3L the biggest sleeper in the Gen III/IV camp. Its cylinder heads flow just as well in ported trim as 5.7L castings. In fact, in the early days of Gen III tweaking, before aftermarket heads became widely available, many enthusiasts preferred 5.3L heads to 5.7L LS1 heads due to the slight bump in compression that their smaller combustion chambers afforded.

For those that see the 5.3L's smaller displacement as a drawback, it has sufficient cylinder wall thickness to easily accommodate the same 3.900 inch bore diamter as the 5.7L. The added durability of an iron block is tough to beat as well.

From 99-07, GM built several versions of the Gen III Vortec 5300, of which the LM7 is the most common. The LM4 and L33 are aluminum block variants of the LM7, while the L59 is a flex fuel spinoff.

GM began phasing in Gen IV 5.3Ls in 05 with the launch of the all aluminum LH6, which replaced the LM4 in midsize SUVs. Then in 07, the iron block, 320 HP LY5 was introduced as an update to the stalwart LM7 for use in fullsize trucks and SUVs. Also that year, the LMG and LC9 were unveiled as flex fuel versions of the LY5 and LH6, respectively. Finally, the LH8 is a slightly detuned 300 HP 5.3L that powers the 09 and up Chevy Colorado pick up.

- CHP