Used LS1 intake manifolds...
Used LS1 intake manifolds are reasonably priced, and if you take advantage of that, you'll need LS1-style injectors. The original truck injectors are too short and have a different style connector.
If you plan to install an...
If you plan to install an LS2-style engine or intake manifold, you'll either need LS2-style injectors (which are shorter and have an EV6, rather than an EV1-style connector) or fuel rail spacers and EV1 connectors that will allow the use of LS1-style injectors.
We used a mounting bracket...
We used a mounting bracket from VettAid, made just for the purpose, to mount the PCM in the engine compartment. Once the PCM was mounted, a VettAid custom harness made wiring a plug-and-play proposition.
Most of these calibration changes cannot be made with a typical handheld reprogrammer, so you'll either need to obtain the required scanning and tuning software, or find an experienced tuner who can build an appropriate calibration and reflash your PCM. Another option is to use a stand-alone aftermarket ECM, but that's considerably more expensive than working with an original equipment PCM, which likely was supplied with the engine.
Whether you plan to use the injectors that were already with the engine or buy another set, it's a good idea to have them flow tested. Unless an injector is brand-new and in its original packaging (and sometimes not even then), you never really know the amount of fuel an injector flows. I've had brand-new injectors that didn't flow anywhere near their rated capacity, and I've had nasty-looking used injectors that were spot on.
Even though we knew the complete history of the LS1 injectors we used, we sent them to Chuck Leeper of Cody Motorsports to clean and test. The injectors had been removed from their original home about two years ago, and even though they had been sealed in a plastic bag and stored in an air-conditioned and heated shop, there was a good chance that evaporated fuel or the always-dreaded foreign matter would negatively affect at least one injector. According to Chuck, the most common problems with used injectors are leaks and poor spray pattern. Electrical problems (internal short or open circuit) are another possibility, although they are relatively rare.
The injectors in this set checked out on-the-money, and that minimized drivability issues. Using a milk crate for a driver's seat (literally, as many people who were at Carlisle can attest), attempting to alter the VE curve for anything other than idle conditions was neither practical nor prudent (although we've rarely let the latter consideration interfere with our plans). But since we knew actual injector flow rate, we didn't have to alter the original VE table very much to achieve good drivability. The only changes required were to accommodate the camshaft characteristics at and just off idle. Had rated and actual injector flow capacities not been spot on, VE table alterations would have been a protracted trial-and-error affair, with error being the operative term.
Following Carlisle, we hauled Project C4orce off to Mid America Motorworks, where it was on display and the subject of a seminar at the company's Funfest event. Prior to Funfest, we sent the car to Performance Choice, Mid America's manufacturing division, where Steve Wiedman and his crew designed and installed new upholstery and gave the rest of the interior some much-needed attention. Steve came up with a clean distinctive design that you'll be able to see in a future issue.