[Formula8]

I only have experience with Holley and here is my advice for anyone contemplating an update to fuel injection on their old muscle car:

1) If you go with a Holley FI system, secure the full instructions off the Holley website rather than the Quick Start guide that comes with the Sniper. I read the entire 75 some pages several times.
2) Get a dry erase board and plan out your wiring.
3) Get the car as close as possible to the way a new, fuel injected car would be setup. Clean output modern alternator (not some '60s-'80s era SI model). Computer connected to directly to the battery and switched on by a relay isolating the Sniper from the rest of the electrical system. Put some care into routing any input sensor (coolant, WBO2 & handheld) wires around other wires. I added ferrite beads and RFI tape around these wires for good measure.
4) No modern car runs an external fuel pump and there is a reason.
5) Your 40-50 year old wiring harness is probably not going to cut it. Be prepared to do a lot of rethinking of your electrical. Holley's marketing makes it sound like a four wire hook up and you're good to go. While that may work for some, now is probably the time to do some updating to avoid future headaches. Most of these retrofit systems have basically zero diagnostic ability and you are your own code reader.....except with no codes to read.
6) Whatever problem you have with your existing engine is not going to be fixed by fuel injection. The problem will likely be worse and you now will be chasing that in addition to a fuel injection system that isn't able to work properly due to the underlying issue. Run a compression or leakdown test, put new plugs, wires, cap and rotor in it and set the timing correctly before starting your Sniper install.