402 Chevy LS2 Short Block Engine Build - Thumper

Once our 'stick was in, we dropped in our new solid-roller lifters (PN 8956-16) with the links facing toward the lifter valley. Next, we began to button up the front of the engine by reinstalling the cam plate and making sure to line up the timing marks. From there, we placed the cam gear back on with the chain, and that's it.

Lift Off
We opted for Comp's new solid-roller lifters for our LS2 mill. This new design delivers a weight savings of 14 grams per tappet over the earlier 8950 Gen III solid-roller tappets, which will help the LS2 to rev even higher, thanks in part to the reduced valvetrain weight. Additional features include an enhanced pressure-fed oiling design, including EDM Oil Injection to the roller axle and bearing, a tool steel axle, and precision-sized needle bearing rollers-and our favorite part is that these are rebuildable.

For added clamping force, we utilized ARP's cylinder head stud kit (PN 234-4317). To install them, we applied moly on both the upper and lower threads, drove them into the block, and snugged them up with an Allen wrench.

Our Trick Flow heads and Fel-Pro gaskets required a three-step torquing method. We began the torquing at 50 ft-lb, went up to 70, and finished at 85. For the smaller studs that run along the top of the heads, we torqued those to 25 ft-lb.

We then installed the rocker studs into the heads, but first placed thread-sealer on the eight studs that actually enter the intake port through the head. Once all 16 studs were threaded, we torqued each one with its guideplate to 30 ft-lb.

Flow For Go
Trick Flow's latest CNC-designed 235cc cylinder heads mean business. Priced at $2,500 for a complete off-the-shelf set, they include 70cc combustion chambers (64cc and 65cc configurations are also available with a 220cc port) 2.08/1.60 intake/exhaust valves, springs, and locks and retainers, and they're ready to run. Check out these massive flow numbers.

Lift Value	Intake CFM	Exhaust CFM
0.100	65	55
0.200	144	124
0.300	229	196
0.400	287	242
0.500	323	260
0.600	340	270

Before dropping in the Comp Cam's 8.22-inch-long, 5/16-inch Hi-Tech pushrods, we ran them through solvent and blew them dry to prevent any potential clogging. Next, we coated each end with high-pressure lube to prevent dry-start.

Westech's Steve Brul lashed our valvetrain to 0.16/0.18 intake/exhaust using a 1/2-inch box wrench and an Allen T-bar.

Up top we forged on with a carbureted Edelbrock Victor Jr. manifold with a Holley 950-cfm HP carb. There's no need to mess with gaskets here. Instead, this manifold integrates the factory Neoprene gaskets into each port.

We couldn't hack seeing the stock LS2 valve covers on this mill. We ended up scouring the Net for something a little more aesthetically pleasing. The answer came in the form of Moroso's fabricated aluminum pieces. If you pick up a set for yourself, know that they still use the main factory bolts and gaskets. We also installed Moroso's trick coil-pack mounting brackets and complete wire set. These slick brackets are anodized and feature a hinge to gain access to the valve cover bolts underneath. This is our first experience with these units, and we don't see us going back to the factory pieces-ever.

In typical CHP fashion we left no options unturned in search of additional horsepower. We used a Holley 950-cfm HP for our baseline pulls and made 589 hp and 534 lb-ft. As testing progressed, we stepped up the cfm and fuel demands by using a Holley 1,000-cfm HP and added a 1-inch Wilson spacer, which then bumped power to 608 hp and 542 lb-ft. However, for all the beans, we topped it off with a Zex perimeter plate. Being conservative, we tested the waters with a 150 shot and produced 744 hp and 763 lb-ft. We didn't stop there. Stepping up to a 200 shot rang the bell with 780 hp and 801 lb-ft!

1. Stock block bored to 4.00 inch
2. Wilson manifold open plenum 1-inch spacer/Zex perimeter nitrous plate (200 shot)
3. Kooks 13/4-inch headers with 18-inch collector
4. Trick Flow CNC 235 heads with Comp 1.75:1 rockers
5. MSD ignition controller with cam sensor swap