Warren, i too am thinking about building a LSX engine, according to the artice below they will handle a 4.5 stroke, for 511 CI, also here are the dim. of the block and other related parts. on a LS1.
Zip.
LSX
At the 2006 SEMA show, GM Performance Parts introduced the LSX engine, an all-new cast-iron racing block based on the LS7 engine. It was designed with help from drag racing legend Warren Johnson. It offers displacements ranging from 364 cubic inches to 511 cubic inches (4.25 in (108 mm) Bore x 4.5 in (110 mm) Stroke) and is capable of withstanding 2,500 bhp (1,900 kW). This block incorporates two extra rows of head-bolt holes per bank for increased clamping capacity. The six bolt steel main caps are the same ones used on the LS7 engine. The engine debuted at the auto show in a customized 1969 Camaro owned by Reggie Jackson. The LSX will be available starting the second quarter of 2007, set to be available in authorized dealerships and retailers on March 31, 2007.[9]
Gen III LS1
Block Length: 519.0 mm
Block Width: 460.0 mm
Block Deck height: 9.240 inches
Firing Order: 1-8-7-2-6-5-4-3
Cylinder bank offset: 0.9488 inches
Block design/main cap mounting: Deep skirt engine block with 4 vertical and 2 side fasteners in the main caps
Rotation sensors: Engine block mounted crank and cam location sensors
Weight: 430 lbs for complete LS1 (Add 88 lbs for iron truck block)
Weight of Bare block: 103 lbs
Connecting Rod: 6.098 inches long. On-center beam rod
Piston-pin diameter: 0.940 inch
Crank thrust bearing location: No. 3 (center) main bearing
Oil Pump: Gerotor, driven off front of crank