But what about the power increase over World's own LS engine? It wasn't all due to a simple port job on the heads. Mitchell reminded us of the differences between the SBC and LS cylinder-block designs. The LS block has a deep-skirt design (also known as a "Y" block"), while the small-block casting extends only to the crankshaft centerline.

The LS block design enhances overall rigidity, which is particularly helpful with OEM aluminum castings, but it creates considerably more crankcase windage than the small-block. The Motown II block is plenty stiff to begin with, with thicker-than-stock key features (bulheads, "China" walls, and more) and four-bolt mains.

"Windage makes a huge difference," Mitchell says. "With this combination, you've really got this best of both worlds-an affordable, performance-oriented bottom end and the great breathing of LS heads."

The implications for the Motown LS are far-reaching for street and racing enthusiasts-and exciting. Just imagine this monster in a C3 or C4 Vette.

World Products deserves an achievement award for the Motown LS, and enthusiasts everywhere are the beneficiaries of the company's progressive attitude toward building big power.









DYNO RESULTS
RPM HORSEPOWER* TORQUE*
3,500 333 500
3,600 347 507
3,700 357 507
3,800 366 507
3,900 375 506
4,000 386 507
4,100 397 509
4,200 410 513
4,300 425 520
4,400 443 529
4,500 463 540
4,600 481 550
4,700 500 559
4,800 517 566
4,900 534 572
5,000 549 577
5,100 562 579
5,200 571 576
5,300 575 570
5,400 575 559
5,500 577 551
5,600 584 548
5,700 595 548
5,800 605 548
5,900 614 546
6,000 620 543
6,100 625 538
6,200 629 533
*PEAK NUMBERS IN BOLD
SOURCE
World Products
Ronkonkoma
NY
6-31/-981-1918
www.worldcastings.com