Holley HOL 12-804 12-804 Fuel Pressure Regulator: Optimal Performance and Fuel Efficiency Review

Holley's printed instructions are mostly for fuel pumps, not regulators. I have found NOWHERE in the docs where the ports are specified, nor on the device itself. 30 minutes of google image search gave me a port identification image. It must be difficult for an old line speed company to identify parts of products. I will never buy Holley products again. Remember another company wants to sell but doesn't support their customers.

I used it on my VW 71 bus It is very well made and although I had some issues with the mounting clamp I used the h2 roof construction clamp. 5 mounted on the fan outlet (on the left in the photo). It offered a right-angle turn for easy access. My only gripe is that there was no thread up front to use the screws, so I took 2 fairly small electrical inserts to keep the screws connected. I might piss someone off, but that's what my litter box is for. Adapt!

Works exactly as advertised. Installation was complicated by the lack of a gauge fitting, which meant an extra fitting had to be fitted somewhere between the regulator and the carburetor to mount a gauge. You'd think adding a pressure gauge port to this thing would be easy enough. There are no threads for fastening screws in the housing. I couldn't get the included self tapping screws and mounting screws to work and had to hand drill holes to install them. Kinda disappointing.

Regulator unfortunately does not reduce fuel pressure as advertised. Like several other reviews, this regulator behaves like a Holley 12-803 at 6-9 psi instead of a Holley 12-804 at 1-4 psi. Returning a regulator required direct contact with the seller, answering half a dozen questions, and spending over $11 on shipping to return a faulty regulator. The seller offered to return the purchase price within 1-3 business days, presumably after receiving it back. If not I will update this review.

This little guy fixed fuel problems with a secondary carburetor on a Willys Jeep. I was able to reduce the fuel pump pressure from 7psi to 2psi and time the carburetor properly. After confirming the fuel pressure, I removed the pressure gauge (sold separately) and installed a 3/8" 18 NPT industrial magnetic (female head) IP-03 drain plug on the second outlet. Adding a 3/8" drain plug Mini Ball Stainless Steel Valves (316) - FxM NPT on the inlet allowed me to use the fuel cut off. The 3/8"…

I use it to relieve fuel pressure in a Weber 32/36 DGEV carburetor. It is designed to drive two carburetors. I disabled one port as I only have one carburetor. I could have hooked up a gauge to an unused port, but I already had a linear gauge installed. Also, with a controller on the firewall, the sensor would be hard to see unless I hooked up a different line. The connections are 3/8" NPT threaded fittings and are not supplied. Adjusting the fuel pressure is very easy. Changing the pressure…

I had a regulator with chrome dials that leaked gas all over the place but luckily it didn't burn my car. Then I got this good one to try and get 1.5 PSI for the Cadron. Everything seemed fine at first, set it to 1.5psi and there you go. I have a sensor on the FPR for monitoring and initially it was great. Later, every time I checked it, I got a different print. That's how I ended up using a liquid-filled pressure gauge installed in the engine compartment. It got hot and gave false readings. I…

regulators purchased from Baxter, unit arrived in 4 days. However, the part number on the box was 12-804, which should be a 1-4 psi regulator. BUT the part number engraved on the unit was 12-804 4.5-9 psi which does not exist. Part number 4.5-9 should read 12-803. I contacted the supplier and he offered to fix the problem. However, I also contacted Holley's support number and was informed that some regulators were mislabeled. Problem with lettering and internal spring. The 12-804 1-4 psi block…