Hello,
I do not post much, but very frustrated and hope to save someone else from similar issues it you are considering EFI. EFI sounds good, but don't.
After months of waiting to get the 69 Camaro I have had since 1974 back from work including the addition of a Holley Sniper Quad "upgrade", I am stuck without the car while it has been to three shops trying to figure out EFI issues. I thought EFI would be great, allow for quick starts, easy warmup, etc. - instead I do not have anything and not much hope of a quick resolution. Since it is not a numbers matching car (back when these cars were not old, we used to change motors any time a bigger one was available), I made a few improvements beyond what I did back in the day, and added A/C, etc. Knowing what I know now, including seeing many issues and much angst about Holley EFI systems on line, I should have avoided switching from a simple Rochester 4 bbl carb.
I had been told it was either the electronic "Breakerless" ignition (which in my general experience either works or doesn't), the Holley unit itself, wiring, programing, etc. - now the latest shop is saying RF interference and they are talking to Holley. This is apparently (from the amount of online chatter) a significant issue for Holley EFI system, especially Sniper units, and can be from all the normal components: plugs, plug wires, cap, rotor, coil, etc., etc.
Fortunately I now do also have another 69 Camaro (convertible with original drivetrain) and 78 Vette and while it takes a little time to warm them up to be able to idle on their own when it is cold, at least I can drive them.
So bottom line unless you have some other very compelling reason to switch to EFI - stay with what you know, straightforward carburation that might run rough, but still run, and worst case, if it cannot be cleaned and tuned, can be overhauled/rebuilt.
