Hey Fellas! been a dam long year rehabing this boat!!!

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  • #46
    Originally posted by Slough View Post

    6.5-8.0 psi, you may need a pressure regulator to keep it from flooding.
    a response from Cliff from my thread over there:



    "After reading from several sources the Rochester needs 4-5 psi and then some have said 6-7 before fuel pushes past the needle and seat."

    This statement is incorrect, actually absurd. Anyone telling you that anyplace is simply very poorly informed, little if any real experience with this sort of thing and simply regurgitating old/outdated information they heard, thought they heard or read someplace (happens a LOT on the Internet on a variety of subjects these days).

    The only Quadrajets that had fuel pressure issues were very early designs and only then when you tried to use huge fuel inlet seats in them. Even the early units with the poorly located hinge pin will EASILY take 6-7 psi with a .135" high-flow fuel inlet seat in them.

    Later models will be fine with larger .145" or even .149" seats to at least 8-10psi without issues. I use a later model Q-jet on the engine powering my Ventura. It has a .145" N/S assembly and fine at 7.5 psi now for over 20 years. This includes drag racing (1.59-1.61 60' times, and hard braking/cornering). In all these years it's never faltered once for any reason.

    Getting past all that a Qjet only has ONE needle/seat assembly so in high performance/high HP applications fuel delivery and the size of the N/S assembly become important. I'm sure during your reading you also heard that the small fuel bowl is an issue, another myth because you are either keeping up or you aren't.

    I've tested Holley carbs with two .110" N/S assemblies/two large fuel bowls against Q-jets with high flow seats and BOTH fall over at high RPM's when fuel delivery is insufficient for the power level of the engine. About all saw with this (did the testing on my own engine at the drag strip) was that the big 850 DP Holley I was testing would go just a tad further down the track before power fell off as it took a little longer to suck the fuel bowls low/empty.

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    • #47
      Very sorry I mentioned it. I know nothing about carburetors or fuel pumps.
      Small town S. W. Ga./St. James Fl.

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      • #48
        Originally posted by Slough View Post
        Very sorry I mentioned it. I know nothing about carburetors or fuel pumps.
        no worries, lol... the bottom line is we just don`t know until its all hooked up. Im picking up the pump today, and my speed shop has a regulator in stock... so all good...

        next season I`ll be running a Carter/eledbrock carb...

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        • #49
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