hillbilly pony

When changing over from fuel injection to carb is it ok to use the stock efi fuel pump and just step it down to carb pressure. If so how much of a step down is to much. my pump is 30 psi constant

I have read that about 14psi is good for carbed cars. but where does the hp to fuel ratio start.

example

if a car has 300 hp and 14 psi is good is it still good for a 500hp car. i guess im looking for someone who knows how to figure that.

WhiteWindsor

Usually 4-7 psi is about the standard. I run 6.5 in my 351. Folk's have used the efi pump before with a regulator. I would not do it just because that is a lot of pressure to hold back for a regulator. The people who have done it swear by it though. I dont know where you could have read that 14 is good for carbs.

hillbilly pony

I guess i may have been confusing the psi of the pumps or something. so 6-7 is enough to keep the bowls full even at high demand?? wow i have some learning to do. with the difference between fuel needs or carb and efi. My carb is from Pro Systems so im hoping it will be good to go. what is your setup??

WhiteWindsor

Yep that's all the pressure you need. I have a 357, ported TW's,vic jr,Holley race HP 750, custom grind- dur @ .050 is 246/259 and lift 588/622 and about 2 pages of other stuff. Pro system carbs are highly regarded, so it should be good. I run a barry grant magna fuel and a holley blue, I just have the other one for nitrous.

my77stang

see the thing with carbs are not matter how radical your motor if you put too much psi to the carb it will push the floats down and let gas in when the floats should be floating.... you end up with a flooding situation.

i'd stick around 5 or 6, and you'll be fine. btw, i have no idea what mine is, but i use a mechanical pump

hillbilly pony

So how does the regulator work. they dont appear to have a gauge on them so do you just turn a screw and watch the external gauge until the pressure is good?

WhiteWindsor

Yeah that's right. I have the fuel and nitrous pressure gauge mounted in cowl.

dukeme

IS it a really big deal to change over to a carb? Is there a kit that you buy such as Manifold, carb dizzy and all of the related parts? I very serious about perhaps doing it? It would sure make it allot easier to work on the motor...
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floodzilla

I have used the regulator set-up before, and it works great. the regulator i got is available from jegs for mustangs and actually has a gauge on it. the only problem with this set-up is that if your pump is very high pressure, i can see it burning out.

hillbilly pony

it has a pressure gauge on it and when the engine is running it says 30psi is that to much??

duke... it is basically very simple to do. just get a carbed mainfold and call up pro systems and get them to build you a carb. ( they are WAY WAY WAY WAY cheaper than any off the shelf with next to 0 tuning ) dizzy and all of that can be modded to fit but it is easier to just get on ethat runs off your MSD. rip all of the wires out...attach the throttle and fuel and go for it. I have used Painless wiring so all of the factory wires areuseless. but there is a web site for the conversion that tells how to reuse the existing wires.