RobbMc 550 HP fuel pump
 

Like other folks here, I've had enough of the poor quality mechanical fuel pumps. At this point, I'm looking at upgrading to the RobbMc 550 HP pump. My 68 wagon is only street driven and I'm putting a 66 Tri-Power on the 400 that's going in it. I just want to take the temperature of folks that have run that pump with a Tri-Power. Which regulator did you use with it (assuming you used one)? Any other tips for using that pump with a Tri-Power?

Thanks
Old Joe

All of the RobbMc parts I have seen are top notch quality.

Running that pump on my 62 Catalina . Bathtub intake 2X4 AFB's 750 CFM. 3/8" stock fuel line, no return, no regulator, no problems in 4 years. Top quality product. I do try very hard to run 0% alcohol gasoline.

I had thought of his concept-mating a valve body on a Pontiac upper years ago when my 455 starved with the Q jet and every mechanical out there.
6 valve on my 383 SBC never missed a beat and what the NASCAR SB used.

I run the high-end carter mechanical on my 505, no issues on pure gas. but i get vapor lock on e10. thought about adding a return but really would rather go with one of the in-tank electrics if i upgrade.

I have a used RobbMc 550 pump for sale if anyone is interested.

I run a RobbMC 550 and a 750 QF doublepumper. The pump pressure can spike to 7.5 PSI and that was giving me inconsistent fuel levels. I put a holley 803 regulator set to 5.75 PSI and it's been steady every since.

Just curious if you had a vapor return on that set up?

I do not. It's a non-AC car so it doesn't have a return line. The PO removed the factory fuel line and replaced with 6AN Redhorse braided line to a pickup that has a 6AN fitting. I wasn't going to run a vapor line since I'm eventually going in-tank electric.

I ran the 550 without a regulator, and couldn't figure out why it would occasionally run rich at cruise, then clean up. One morning I cold fired it and watched the sight glasses. The fuel level went to the top, and then after a few minutes dropped to less than half. Hmmm... A gauge showed the pump spikes over 7 PSI at start.

With the regulator, the gauge is rock steady up to 6 PSI. When set to over 6, the needle bounces in time with the fuel pump. So I set it just under 6 and it's been great.

The next thing I noticed is the AFR was much richer at WOT. Even after changing air filters and air cleaners to a very low restriction domed design, and going to a 1/4" open spacer, the WOT AFRs were still rich. I ended up dropping 1 jet size in front and back to lean it out. I'm guessing the fuel levels were dropping at WOT with the cheapo parts-store pumps, and I was jetting up to compensate? It makes sense to me, because in my previous 67, the same type of pumps would run a Q-jet completely dry at the top of 2nd.

66 GTO 461 with tri power
I used 1/2 fuel line and a return...robmcc filter and regulator
The carbs are only happy with 4.5 lbs pressure and don't perculate or hot soak at all...it's perfect