Well the end of the road for Project C5X has finally come. As most of you know, this project began almost 2 1/2 years ago, and we have been on a long journey to upgrade Project C5X on a lot of different levels. That journey included a Mid America Motorworks (Performance Choice) interior upgrade, Pfadt sway bars and coilovers, an American Car Craft stainless steel accessories package, a Baer brake upgrade, basic engine add-ons including Dynatech headers, Mid America Motorworks exhaust and air intake, an Elite Engineering tunnel plate, and an MTI shifter install. Almost all of our installs, and 100 percent of our dyno work, was done by Next Level Performance in Altamonte Springs, Florida, and Geoff Skorupa and crew have done a superb job! We covered lots of editorial ground, but what we really want to do now is to bring this project to a close by installing the last go-fast parts on the car and produce some real horsepower on the dyno.
Before we can really say goodbye, we need to cover the installation of our new LS1X World Warhawk heads and custom grind C4orce Comp Cams hydraulic roller camshaft and valvetrain. To backtrack just a little, most Corvette owners realize that the LS1 is the perfect candidate for making power. The LS engine has been one of the most easily modified engines ever built and with every new LS generation, Chevrolet keeps improving the breathing ability, thus making it that much easier to make easy gains with very little effort. The original LS1 engine is still residing in Project C5X and we always knew we could make some good power with our almost-stock LS1 engine.. so early on, we decided the most prudent use of our time and energy would be to build the stock engine we already had instead of swapping in a brand new LS stroker.
We first removed all the American Car Craft stainless panels.
Prior to the head and cam install, we installed a new VMax Motorsports throttle body and we wanted to see what kind of horsepower it would mean to a near-stock Corvette. After we got that install nailed down and dyno'd at about 7 RWHP, the head and cam upgrade was up next. A head and cam upgrade is one of the simplest and most productive upgrades for any car but especially so for the LS1.
There are lots of choices out there today for this type of swap. We wanted to try to find the cheapest horsepower for the money, so we looked very hard at all the aftermarket components available for the LS engine. After some consideration, we decided to try a set of the LS1X World Warhawk heads and a custom grind C4orce Comp Cams hydraulic roller camshaft and valvetrain. Pete Incaudo, owner of VMax Motorsports, worked on the development side for the LS1X World Warhawk heads, so that made our cylinder head choice a little easier. The World Warhawk heads we used had the 72cc combustion chambers and feature 235cc intake runners similar in design to the cathedral port of the LS1 and LS6. We would have liked to have used the 64cc version with a smaller intake runner, but it was not currently available at the time of this build.
Engine with heads now removed.
Pete also had to angle mill these stock castings to arrive at an optimum 62cc combustion chamber that yielded a 10.5:1- 11:1 compression ratio, which is fine for the street. The combustion chamber in these heads is fully CNC machined. On the exhaust side, Pete hand ported and polished the short side radius and intake runner entry to enhance flow through the intake without enlarging the port volume. On the intake side, the port received minor work on the short side radius and floor with enough material removed to eliminate the casting lines. As Pete was working on the heads and checking for pushrod clearance issues, he found that there was interference with the casting. He then had to hand grind the pushrod opening and unfortunately, since the casting was too thin in that area, to get enough clearance he broke through all the intake port walls. This had to be repaired by welding a new wall area around the pushrod opening to alleviate the problem.
The World Warhawk LS1X heads are set up for 2.08/1.60 valves and in this install, Manley Performance valves were used. A Comp Cams LS1 Dual Valve Spring Kit with titanium retainers and their machined steel valve locks were also used. We also used Comp Cams Hi-Tech pushrods, and we decided to try their killer Ultra-Gold CNC-aluminum 1.72 Ratio GEN III Rocker Arms for this build. Due to the fact that the stock LS1 pushrods will not work with these heads, you need to make sure you measure for correct pushrod length because of the difference of the rocker arm rail height of the World heads, and because we had to angle mill these heads to get the compression correct.