I just got done puting the 350 into my yj. i used the advance adapters saddle motor mounts, which do not allow use of the stock mechanical fuel pump. I am totally broke now, so i really dont want to shell out a hundred bucks for an electric fuel pump. my dad, who is into porsches suggested that i use a ball valve with a three way to lower the 50 psi from my electric pump down to the 5 psi that i need at the carb. he says that some of his porsche buddies use a setup like this to convert a newer fuel injected porsche to the old style weber carbs.

the basic concept of it sounds pretty good. you put the ball valve with the three way up near the carb with a fuel pressure gauge. then you use the stock jeep fuel return line to bleed off the excess fuel pressure back into the tank. he says that with simple adjustment to the ball valve, you can adjust the fuel pressure you are getting at the carb.

It sounds pretty good to me, and porsche guys supposedly do it all the time. what do you guys think about it?

Just suck it up and buy a Holey Blue pump wih a cheap regulator. it is a simple, proven method and comparativly cheap.

Use a spacer and vette (or other really long) throttle cable to mount a Q-jet backwards on the intake. Regulate donw to next to nothing FP wise and it actually behaves pretty decent, just remeber to turn the FP back up before tryng to merge into traffic on the road :)

the throttle cable is not the issue here, i have a holley double pumper mounted on it right now, the throttle linkage should be fine.

the throttle cable is not the issue here, i have a holley double pumper mounted on it right now, the throttle linkage should be fine.

If you wheel on anything more then a 3% grade you are going to regret that choice.

For power, throttle response and tuneability you can ot beat the Holley. Unfortunatlly due to the style of float bowls and fuel metering the Holley can not match the Q-jet for off angle operation.

got propane? no puel pump required.


the porblem i see with using a simple ball valve is that you may get 5 psi at idle but anything off idle and you will see a sudden drop in fuel pressure as the needle assembly opens. the reason is because with a ball valve you wont be reducing the pressure actually but the volume of flow.

you could probably regulate teh 50 psi down to 5 psi with a proper 3 port regulator but that will be more expensive than a holley blue pump and cheap regulator.

is there absolutely no way to address the clearance issues to fit the mechanical pump?

if its just a promlem with the inlet hitting the moutns then maybe a stock early carbed camaro pump will work, the inlet is on the bottom.

I really appreciate the help. propane is the way i eventually want to go. i figured i would get it back on the road running it on gas, and switch to propane later when i get more money. from what i have heard, propane woud not make much power with a lower compression ratio (9:1) like what i have got.

Dug, is this carb really going to suck that bad on hills? I have the crappy old Q jet that came with the engine that i could still use. i just thought it would not be that bad, especially since i am only using it until i get the propane setup.

I guess i didnt really think about what would happen with the ball valve if i was on the gas for enough time to run the float bowls dry. they say that this carb will run at a minimum of 2 psi and a max of 6 psi. do you think if i set it at around 6 psi at idle it would flow enough fuel to keep the floats up when i am on the gas?
I am starting to think about holding off on all of this rigged bs until i can get enough money for a propane setup.

oh yea, the motor mount i have is the saddle kind. it barely clears under the front of the oil pan, so clearance is too tight to fit the mechanical pump. it is hard to even get in there to put the block off plate on it.

+I think it iwll be that bad.... Holleys can be setup to work OK off road but you need to buy a bunch of crap and tinker with them. The Q-jet you just have to bolt it on and never look back, very much worth it IMO. You you are caught up on making great power a Q-jet can be tuned to work like a champ in that respect to.

Propane will make perfect power at 9:1, in fact at 9:1 you shouild not see an appreciable drop in engine perfromance. There will be a small one but hardly enough to notice. LP conversiosn just need to thave the proper timing and advance curve to make good wpower as well as have the mixer setup properly.

OK, i will get the Q jet out of the garbage can. I will just use it until i gather up all of the stuff for propane. how much fuel pressure do you think i could put into a Q jet at idle before i start to toast the seals in it? Reason i ask is because i still have some hope in the ball valve thing.

It is not a matter of blowing the seals in the carb... it is a matter of pushing the needle off the seatand then overfilling the float bowl till it comes out the vent tubes.

I would say you need ot be in the area of 4PSI for street use, if it starves under load from lack of fuel raise the pressure a bit.

I agree with not using the ball valve. Like said before, you are limiting flow...not pressure. Holley makes a nice fuel pressure regulator that I used for my old NOS setup. I'm not sure what the max input pressure is, though. There are fuel filters that have three ports...One is the inlet, another goesto the carb, and the third is a return back to the tank. These are used on some carb setups and might work for your application. I don't know exactly whats inside the filter but from my understanding, they bleed off the excess fuel back into the tank when the needle valve is closed. This should eliminate the problem of the high pressure pump forcing the needle valve down and flooding the carb. I see no reason that your electric pump can't be used. The one thing about those pumps, though is that they want to circulate fuel all the time (They will overheat if the fuel isn't moving).