[68GMCCustom]

the old sbc and bbc are great motors...but the genIII and genIV "small blocks" represent the modern versions. Of course you can get a 620hp 572...but you can also get a much lighter, smaller, LSX 454 with...620hp. Less cubes, less mass, same hp. And yes, the 572 can make 720hp at 12:1...but the LSX 454 can also be improved upon and still run pump gas...not to mention the block is rated at like 2000+hp. The aluminum blocks can take big power too... but the iron 6.0L truck motors are a better choice for forced induction and/or nitrous.

So...back to the question......whats the big difference in the old motors...and pitching a bbc against a LSx? The LSx motors have finer tolerances, roller cams, and better rockers...all for less friction. 6 bolt mains for strength. The heads....well they flow big numbers...like a bbc. The ignition is not only generally computer controlled, but theres a coil just inches away from each plug for better spark, better timing control. Another neat tidbit is 4.8L or 7.4L+.....it all fits in the same size package!