Cast-Iron LSX Block - Low Buck Brawler

The main bearings are lubricated, and the crank lowered into position. This Eagle unit is a non-twist forged unit constructed of 4340 alloy steel and equipped with micro-polished journals. "Although there are more expensive cranks on the market, the Eagle offers great strength and value for the dollar," says Mangum. "We've used it in forced-induction applications that exceeded 1,000 horsepower without failure." Both 24X (used here) and later 58X reluctor-wheel versions are available.

The piston-ring set comprises Total Seal units with a plasma-moly-coated top, Napier second rings, and cast-iron oil-control rings. A motorized piston-ring grinding machine is used to set the gap at 0.021 in on the top ring and 0.023 on the secondary. The oil ring and scraper are installed, followed by the two top compression rings on a set of custom Diamond Racing flat-top pistons. This forged offering uses 2618 alloy with 4cc valve reliefs and can handle up to a 200hp shot of nitrous with the specified rings. (Custom -10 and -28cc offerings also available for lower-compression or boosted applications.)

Eagle H-beam forged 4340 connecting rods weigh a scant 620 grams and use 0.927-inch free-floating wristpins from Diamond Racing/Trend Performance. ACL rod bearings are installed, and rod-bearing clearance is verified to be 0.0025. Once each rod assembly has been checked, assembly lube is placed on the bearing surface, and the builder prepares to install the pistons.

Before piston installation, the bores are wiped clean, and oil is liberally applied to the piston skirts. A tapered ring compressor is used, and the crank is rotated into position so the piston and ring pack can be inserted in the bore. The rod is then carefully slipped over the crank's rod journal, and the rod cap is installed with ARP 2000 bolts, which are loosely tightened. Once piston/rod installation is complete, the rod bolts are torqued to 70 ft-lb. The bearing-cap side bolts are then installed (five on each side) and torqued to 18 ft-lb. Once complete, the crank end-play clearance is measured.

A dial indicator is set up on a bridge over each piston, and the piston-to-deck height is measured. Texas Speed specified a positive 0.005 clearance, which is verified on each piston.

After ensuring that the dot on the crank keyway is at the top, a custom hydraulic roller camshaft from Comp Cams (242/248-degree duration at 0.050, 0.612/0.615-inch lift, 111-degree LSA) is thoroughly lubricated and carefully guided into position.

The cam is retained with a thrust plate (GM PN 12589016) that was redesigned for the Gen IV engine family. Instead of four 10mm bolts, the new hardware features four counter-sunk T-10 metric bolts, which are torqued to 19 ft-lb. A new cam gear (GM PN 12576407) and an LS2 timing chain (GM PN 12586482) are also utilized. The cam is rotated so that the dowel pin lines up with the cam gear. The timing chain is then slipped over the gear, and the assembly is rotated so the timing mark on the bottom of the cam gear lines up with the dot on the crank gear. Loctite is then applied to the new ARP cam-gear bolts, and the gear is torqued to 30 ft-lb.

Rather than using a stock oil pump, TSP employs a ported LS6 unit (PN 25-12586665M) that offers increased volume and pressure (by about 10 psi). Note how the pump's pickup is lubricated with Red Line assembly lube. The crankshaft bolt is removed, and the oil pump is turned into the correct position before being slipped on. The four oil-pump bolts are then torqued to 18 ft-lb.

New GM lifter trays are utilized along with LS7 hydraulic roller lifters. After lubricating the housing and roller portion of the lifter with assembly lube, the lifters are pushed into the tray and then fitted into the block. After all four lifter trays are in position, the single 10mm bolt that retains them is torqued to specification. The block is then fitted with two new GM head-aligning dowels (PN 12570326) per bank, and the block surface is wiped clean with acetone. TSP then places GM MLS LS7 head gaskets (PN 12610046, sold individually) with a bore size of 4.125-inches over the dowel pins in preparation for head installation.