Holley 550510 Electronic Fuel Injection

I installed the Holley Sniper EFI and the Holley Sniper Fuel tank on my 1971 440 Cuda mainly to get rid of the gas smell from my car. The carb ran good but after driving the car you and the house smelled like an old gas station. I followed the Sniper installation video exactly and to my surprise she fired right up and ran perfectly right out of the box. I drove around to let it self tune and can't be happier with the way the Sniper performs. No more cold start problems, no gas smell, better gas mileage and more horsepower. The only tricky part was finding a 12V source during cranking and run. Old Mopar's don't have a single source for that so I had to come off two sources and run thru a diode. The only negative I have on the Sniper EFI system so far is that my EFI monitor will automatically switch to a different screen after driving for a while. I'm not sure if this is by design or some issue with my system. If it weren't for this issue I would have given it 5 stars

I'll give it 3 stars for now as it is installed on my vehicle but I can't turn my vehicle on yet because I am missing 2 important wiring harnesses that never came in the box. I am missing Part# 558-491, Output Harness, and Part# 558-490, Main Harness and Ignition Adapter. I have no way to test the new EFI and don't know how they could miss the 2 most important harnesses. It looks cool sitting on my engine but that's about as far as I got as I cannot test it without the harnesses. Maybe someone at Holley will read this as there are similar complaints for the same missing parts. UPDATE: issue solved Holley shipped the harnesses I needed in 2 days no charge.Update: Unit back at Holley after sending 28 emails back and forth with the tech to get them to open a ticket. After chatting with tech over phone and email for 2 weeks he finally admitted that 10-20% of the sniper systems have issues with tuning. What a waste of time and money, why not admit that upfront and take it back to bench test and fix. Either way car project has been done for over a month now after a year of rebuilding for an EFI system and other items just won't be able to drive it until Holley fixes the sniper unit and gets it back to me. Overall pass on this and spend the money for a ProM unit.

The kit did not include everything, so figure it's really going to cost you over 2k$ to get the old boat running. But now the car starts without any blue or black smoke out the tailpipe, runs smooth, I now have 14 inches of vacuum instead of struggling to have enough to not open the power valves all the time, I cannot explain this. I think the kit should come with the progressive linkage instead of the "all barrels all the time' linkage. I took the back barrel linkage off and am only running the front two barrels till I get the progressive linkage. I may have to update the chip for the progressive linkage to dial in properly, but so far it runs good on two barrel.

Installed on my 1978 f150 with a 400. Not bad to instal. I went through a car wash 2 weeks after installing it and it killed the throttle position sensor. Hood wasn't up or anything so I don't know how that did it. The throttle position sensor was on backorder to so 2 weeks of the pickup sitting.

The first thing I noticed was the finish on this unit was not nice and shiny, but rather looked like someone painted chrome on plastic with spray paint. Not like a billet finish or anything (I'd consider opting for black if you're buying). I installed it and immediately had problems. It ran terribly and leaked fuel from the crossover hose. Initially, Holley wanted to charge me shipping to send it in to fix it (unbelievable). But after some complaining they decided to comp the shipping and several weeks later I got it back with a new fuel pressure regulator and a new crossover pipe. It no longer leaked, but I didn't even get to start it. When I hooked it all back up I noticed the TPS was reading 100 and wouldn't budge. That's right, after being at Holley for weeks getting fixed and checked to make sure it worked properly, I got it back with a new problem. Holley sent me a new TPS (overnighted, which was nice of them) and I installed it. It fixed the problem, and now, almost 2 months later, I finally get to use the system I bought. Needless to say, all the talk about plug and play and the ease of use was false. I spent a lot of money to get rid of my carb and inherit problems.As far as installation went, it was relatively easy. I wished the harness and relays were of better quality and were more customizable, but just a small gripe. Now that it runs, it runs relatively well. It definitely starts faster than the carb and runs cleaner. The idle is more erratic than the carb though. Overall the benefits haven't outweighed the problems and the cost. I would suggest doing a lot of research and tempering your expectations before purchasing.

Installed this product on a 350 chevy and it is incredible. The ease of installation and the self-tuning capability truly make this a carburetor killer.IF YOU BUY THIS OFF AMAZON TRIPLE CHECK THE BOX FOR ALL PARTS, I RECEIVED TWO, YES TWO, BOXES IN A ROW MISSING THE MAIN WIRING HARNESS.Luckily Holley over-nighted me the missing harness, but I can't guarantee they will do that for all.

Huge difference @ idle and performance over the edelbrock. In all fairness, the edelbrock was out of the box and never tuned, other than idle speed and idle mixture adjustment. Installed on 880 block vortec 350, roller cam, ~10.51 comp. Borla headers/exhaust etc.

Installed unit on car, barely ran. Emails are answered in 3 to 5 days, response is, call technical help phone number. I tried this phone number 50 or 60 times during business hours, "call cannot be connected at this time, try again later".

J'ai acheté ce produit l1 1 mai 2017.et il ne fonctionnaient pas, il mon retourner une nouvelle pièce qui bien fonctionné 2 semaine environ et la elle est encore défectueuse... je ne conseille pas du tout ce kit.