Holley Sniper EFI
The 1967 Camaro was born with a single barrel carburetor and inevitably rebuild with a Holley 600CFM Double Pumper with Mechanical Secondaries. That carburetor actually worked pretty well, but not only was it difficult to keep in tune as a daily driver in different areas and rapidly changing weather conditions, it never really fit the build. Turbo Camaro has always been about custom upgrades and improvements over stock. While not saying a carburetor doesn’t have it’s place, it just isn’t a modern choice for a car peeling away from stock.
Dozens of hours were spent researching available Electronic Fuel Injection (EFI) options. With most popular options starting at $999US you can get in the market easily but once you commit to a specific system or brand, you are stuck with it unless you intend to buy multiple systems. With FAST, Edelbrock, Holley and FiTech competing with each other, it opens the door for very similar products, making the choice that much more difficult. For a basic recount of the standings, FAST was early to the game but has since fallen short. Edelbrock also released a decent system but performance results were sub par. Holley had several high priced units with success but the lower priced Sniper unit was new and unproven. FiTech had one of the first budget priced quality units to perform well, but doesn’t match the newer Holley Sniper features/specs. Most specifically the injector ratings, laptop software and AFR grid sizes. At the time of consideration, early reports indicated users had improved learning and performance with the Holley Sniper. One of the biggest considerations is the name brand. Normally we don’t care much for brands, but when it’s Holley vs. FiTech it’s a big deal. Which brand has been in the game longer, and which one will still be there, supporting products in 10 years?
We sourced our Sniper Master Kit from www.efisystempro.com
So we went with the Holley Sniper EFI Master Kit from EFI System Pro. It won’t seem like a big deal 5 years from now, but EFI System Pro actually had stock on the Sniper when nobody else did, and the price couldn’t be beat. Their customer service helped me realize I’d need an extra EFI fuel return line and a Can to USB dongle cable for live tuning the fuel and boost tables. That being said, upon release, the Holley Sniper system didn’t support a blow through turbocharger as the base software tables didn’t include presets for boost. With the addition of the Holley Tuning Software, you can use the dongle cable to get the job done. Beyond that, the Sniper can run up to 650 horse power. Technically the built in injectors can handle a lot more, but internal restrictions apparently don’t keep up well much beyond the 650 point.
With the Sniper unboxed, it was time to do some comparisons against the trusty Holley 600CFM. The inline 6 has limited space on the passenger side of the intake as it sits almost up against the valve cover. You can see in the image below that, unfortunately, the Sniper system puts the linkage out an additional ½” or so.
Of course a consideration for anyone is height vs. hood clearance. Various sources say the Holley Sniper is about the same height as a typical carburetor, and they’re right. Our comparison below to the real deal proved just that.
A solid weekend later, the Holley Sniper EFI system and Master Kit was installed in the camaro. Rather than reading the outcome, take a look at our how-to video:
With the Holley Sniper EFI running smooth, we really want to set it up to control timing but not all options are equal in desirability and some simply aren’t compatible with our Inline 6.
Option 1: Holley Dual Sync Distributor (DSD) with hall effect trigger and a stand alone coil. This is easily the best route if you want a hassle free install that just works. Most forums and parts suppliers will suggest you go with a DSD as it’s hall effect trigger is immune to common radio frequency interference that plagues its magnetic brethren. Unfortunately Holley has yet to craft a DSD for the Chevy 250.
Option 2: MSD Distributor with magnetic trigger, stand alone coil and MSD Rotor Phasing Kit. This option would probably get the job done, but considering the cost of all the parts required, and to end up with a magnetic pickup, it just doesn’t seem like the best bang for buck. If you already had this distributor then obviously you should lock it out and give it a whirl, but I wouldn’t want to buy this for a new build if a DSD was available.
Option 3: Large Cap GM HEI Distributor with magnetic trigger and built in coil, manually phased. This is obviously the cheapest, but requires taking the road less traveled. By “less traveled” I mean someone’s been on it a couple times and the footprints are faint at best. Very little information exists on the “best” way to setup a coil in large cap HEI distributor for timing control, but it has been done by at least a couple people and seems to work well for them. This would obviously be the cheapest method but requires some ingenuity.
For more information about wiring the above ignition options I recommend checking out Demystifying Holley Terminator and Sniper Ignition Hookup or referencing the official Holley Forums.
For a complete video tutorial covering all aspects of electronic timing control with a GM HEI Distributor and the Holley Sniper EFI System take a look at our video: