LT1 Block and Cams - LT1 Cam-O-Rama

As soon as we were done wringing the most we could out of the Edelbrock intake, we left the big cam in there and installed what we lovingly call the "bread box" intake. We honestly had no idea how it would fare compared to the beautiful red intake that had performed so well. Not surprisingly, the gurus from the big E knew their stuff as their LT4 intake bested the bread box through almost the entire rpm range ... until 5,900 rpm that is. From there on up, the bread box did as it was designed to do and was able to feed just a little more air to the mill and pick up just a couple of horses. Was it worth it? Maybe, if you plan on using only a high stall converter and revving the wee out of the engine. Otherwise, save a bunch of time and effort and stick with what papa Vic puts out.

The heads use lightweight 8mm valve stems with 2.02/1.57-inch stainless steel valves and beehive springs that according to our spring tester were easily good for more than .600 lift. They have fully CNC-ported combustion chambers as well as CNC-blended intake and exhaust runners. The only issue we had was that the large 195cc runners had a port entry that was larger than either the LT1 or LT4 intake gaskets. This was easily remedied by using a set of Felpro 1206 gaskets, and punching out a new set of boltholes in them. With flow numbers better than the factory LT4 heads and much less scarce, it makes the Edelbrock heads an easy choice.

The Edelbrock LT4 intake manifold is every bit as nice as the heads. It uses an Air-Gap design to cool the runners and plenum and accepts all the factory sensors and bolt-ons as well as a 58mm throttle body without any extra grinding. A super nice red powdercoat mimics the finish of the GM LT4 intake. No port matching was required to mate the Edelbrock intake to their heads. Though they suggest some matching may be required if using this intake on factory heads. Together, the pieces of the Edelbrock top-end kit form a perfectly matched combo clearly capable of massive power.

There are a number of options for triggering the ECU. After lengthy searching, we found a way to run it based off the Optispark pickup, but we wanted something a little simpler. Following the do-it-yourselfer attitude of the Megasquirt world, we rounded up an old Holley hall-effect crank trigger wheel, scavenged a crank sensor from an LS1 engine, and cobbled up a sensor mount. Correctly assuming there would be a learning curve, we got everything together on our run-in stand instead of wasting precious dyno time. The initial setup was fairly straightforward, and the engine fired up without much effort. The problem came whenever we tried to rev it above 3,000 rpm and it would stutter and stumble. After lengthy calls to EFI-Source tech dude Scott Clark-aka "Dieselgeek" on the boards-we went through a couple of different crank triggers and sensors, but it turns out we were just getting noise in the crank trigger wires from having them routed too close to the injectors. A quick rerouting and the engine ran like a dream. Tuning changes were quick and easy, and most didn't require turning off the engine, though I wouldn't suggest that technique in a moving car. For just over a grand, we had a fully optioned ECU with 12x12 resolution tuning tables that worked as good as anything on the market.

The distributor isn't the only place where MSD is moving forward. Recently, they unveiled their 6AL-2 ignition box. Destined to take the place of the venerable 6AL that has been a staple in racing and hot rods for years, the 6AL-2 uses digital technology instead of an analog design. This allowed MSD to put additional features like a built-in two-step and optional hall-effect trigger pickup into a smaller case. More features, less space, what's not to like? As always, they even went through the effort of printing their wiring diagram on the back of the box for those of us who immediately destroy all instructions upon receipt.