How much fuel pressure?

[Swampdog]

I have 62 383 with 2 four barrel carbs. They are AFB's, 3258 and 3259. I am installing a Holly blue electric pump and regulator. The instructions say it is set to 11 PSI. I know the old mechanical wasn't near that high. What would be a good setting?

5-7 PSI?

I am installing the electric pump to cure the dry start problems.

 

[silver67]

6-7 works for me.
505 bbm
Street strip bracket

Cross the stripe about 5.5 pounds going 120 mph

Same pressure with my old Edelbrock 800 single four

 

[Grabinov911]

I think 5 to 7 is right for Holley carbs. Assuming that you are running the electric pump as a simple replacement for the mechanical, I think you are probably fine there for the AFB's as well, particularly if you're not running a return line with the goal of cycling fuel back to the tank. It IS possible that you'll need to go a little higher to get the volume you need for two carbs, but I think you'll know pretty quickly. First, does it idle without emptying the float bowls? Then, does it high-idle (in your garage at say 1,500 rpm) without emptying them? Then, does it road test without starving for fuel...

 

[Yatzee]

I have 62 383 with 2 four barrel carbs. They are AFB's, 3258 and 3259. I am installing a Holly blue electric pump and regulator. The instructions say it is set to 11 PSI. I know the old mechanical wasn't near that high. What would be a good setting?

5-7 PSI?

I am installing the electric pump to cure the dry start problems.

If you run 2 four barrels it will depend on volume required not pressure. It may well take a higher setting of pressure to put a given volume down the same pipe for the two carbs. 9 -11 sounds about right if a single carb requires 5 -7. You'll have to test for fuel starvation under all operating conditions and a static gauge is highly recommended.

 

[727]

That fuel pump is noisy.

 

[early2drsedan]

carters dont like more 5-6 pounds or they blow the the needle and seat over and drown the motor

 

[lewtot184]

keep the pressure at 5-6 and you'll be fine. I think the real fuel pressure problem with the AFB's is more related to edelbrocks version. they use the small brass float and I don't think it controls as good as some of the earlier carter made carbs with the larger brass float.

 

[khryslerkid]

keep the pressure at 5-6 and you'll be fine. I think the real fuel pressure problem with the AFB's is more related to edelbrocks version. they use the small brass float and I don't think it controls as good as some of the earlier carter made carbs with the larger brass float.

Not to totally hijack but I'm useing the Carter m6903 and it states maximum pressure is 6 - 7.5
I have two 600 Eddies

Should I use a pressure regulator or get a different guage?


https://www.summitracing.com/parts/crt-m6903

 

[lewtot184]

Not to totally hijack but I'm useing the Carter m6903 and it states maximum pressure is 6 - 7.5
I have two 600 Eddies

Should I use a pressure regulator or get a different guage?


https://www.summitracing.com/parts/crt-m6903

I have the same carbs with a 6903. 6903's only do 5-6psi unmodified. you may have a gauge issue, but if your not having any problems i'd just make note of what you got and not worry about it. those carbs have .093" needle and seats with the small floats. seems as if the small floats handle the smaller needle and seats o.k. small floats and .110" needle seats may have an issue around 7+psi. I tried .110"s in my carbs and didn't care for it; went back to .093". the original 440 avs's had big needle and seats (340 and 383 didn't), big floats, 8lb pumps with a return and this combo seemed to work o.k. I use a return with my quads and 6+ psi 6903 pump. no issues. returns do help.if I was swampdog i'd just put a 6903 pump in it and call it a day.

 

[62 Dart Convertible]

I have 62 383 with 2 four barrel carbs. They are AFB's, 3258 and 3259. I am installing a Holly blue electric pump and regulator. The instructions say it is set to 11 PSI. I know the old mechanical wasn't near that high. What would be a good setting?

5-7 PSI?

I am installing the electric pump to cure the dry start problems.

I went electric pump also to cure my dry start problems with the exact same pair of carbs, though I used a Carter electric pump that required no regulator. No regrets. I'd adjust regulator for 5-7 psi and would highly recommend a return line to tank. Does regulator have a return provision? If not a Wix 33040 fuel filter works a treat.