Edelbrock LS1 Heads And Exhaust System - Gen III Recipe

A 10mm socket removes the coolant crossover...

...and then Alfred takes off the valve covers and rockers with a 8mm socket.

Each head has five 10mm bolts and ten 15mm bolts holding it to the block. Sandwiched in between are graphite head gaskets. Only in 2002-and-later LS1s were the more desirable MLS head gaskets used....

...Pieces of graphite need to be peeled and scraped off the block after removal and prior to installation of the new heads to form a good seal. Some coolant inevitably gets on the pistons, which needs to be cleaned off before installing the new heads as well.

Since this is such a high-mileage car (78,000, to be exact), ESP doesn't want to take any chances with the lifters later on when the cam is installed--so the lifters and trays are replaced with a used low-mileage set purchased by the owner. A single 10mm bolt holds each tray in place. High-mileage cars tend to stretch the lifter tray out enough that the lifters will slip out when the cam is removed and fall into the oil pan. This disaster forces you to pull the whole motor out to fix it, so purchasing new lifters and trays is cheap insurance.

The new graphite head gaskets are put in place along with a set of ARP head studs. Since the stock head bolts are torque-to-yield, they are not reusable; however, the ARP head studs are (in addition to being much stronger).

The spark plugs were transferred over from the old heads, as were the head dowel pins, before installing the Edelbrock heads. The washers and stud heads are greased with the supplied lube before fastening the large outside studs to 15 lb-ft to get the heads seated, then the smaller studs to 30 lb-ft. All the studs are then re-torqued to 70 lb-ft.

The pushrods and rocker arm assembly are installed with a little dab of grease on the tips of the pushrods. The rocker arm bolts are then torqued to 22 lb-ft. Normally, ESP would cut the rocker arm bolts since they protrude into the intake path, causing turbulence and decreasing flow (Edelbrock will release a set of accurately sized optional rocker bolts to prevent the bolt from protruding into the port). However, we later discovered another reason to trim these bolts--this pre-production set of heads had significantly shorter bolt holes, causing the rocker bolts to bottom out before they were completely tightened down. We're told production pieces won't have this problem.

After the top half of the motor was put back together, the oil was changed, the radiator was refilled, and the TA was strapped to ESP's Dynojet. The Chef's new recipe made just shy of 54 horsepower and 41 lb-ft of torque without changing a single component besides the heads. Peak numbers went from 306.4 (SAE) to 360.3 rwhp, and 317.5 to 358.7 lb-ft in the six-speed TA. When Alfred later took the valve covers off, he discovered the rocker arms were loose and sliding off the pushrods. This meant the cam might have been robbed of some lift when we had it on the dyno. At first, Alfred thought a shorter pushrod would be necessary to compensate. But, as previously mentioned, the problem was the length of the rocker bolts.

To install the cam, the rocker arm assembly and pushrods had to be removed, as well as the water pump and radiator. The coolant, A/C condenser, and oil are drained prior.

The radiator cores are unhooked and removed.

The air pump is permanently removed for weight savings. With the water pump out of the way (via its four 10mm bolts), the timing cover is exposed.

The crank pulley must come off with the pulley removal tool, and finally the eight 10mm bolts on the timing cover with a wrench/socket.

A 15/16-inch socket turns the crank so that the timing set can align. Three 10mm bolts hold the sprocket in the timing set, four more 10mm bolts on the cam cover, and the cam is turned out of the block...

...The owner chose a very common street cam with 224/228 duration at .050, .569/.572-inch lift and 113 LSA...

...This COMP Cams bumpstick was selected because it was neither too tame nor too aggressive for use in a true daily driver.

Since three different cams were in this block prior to putting the stocker back in place, the threads in the bolt holes for the cam cover were stripped. In addition, the cam cover itself broke at its bolt holes. The holes in the block were rethreaded with a Helicoil thread repair kit, and the cover replaced. Once the timing set and cover were back on, the crank pulley was torqued to a whopping 240 lb-ft.

The exhaust manifolds were then installed with these 1 3/4 to 1 7/8-inch stepped long tube headers. These Edelbrock Victor Drag Race Headers also have a slip-on 3 1/2-inch collector and are made of mild steel with a Ti-Tech finish. Notice the Nascar-style spike merge collector; these headers mean serious business...

...Not shown is the Competition Y-pipe, which is a 16-gauge aluminized steel, catless, off-road piece. The kit came complete with metal exhaust clamps to tighten all the slip-fit connections, and O2 bungs.

The headers were a tight fit on the driver side, and the ARP head studs were making the install near impossible. Alfred removed the oil pressure block-off plate with a 10mm wrench, but it did little to help the situation. Ultimately, Ken employed the "Fonzie method" and we were back in business. Meanwhile, the passenger side slipped right in without a problem.

Once the gaskets were installed and the header bolts tightened, Alfred assembled the Y-pipe and merge collectors.