A TIP FOR THOSE WHO ARE "CARBURETIONALLY CHALLENGED"

[D.Hearne]

Two weeks ago I pulled the 331-sixpack motor from my 89 Ranger and replaced it with my "spare" 5.0 to, so to speak, "detune" the Ranger to use as a pickup again. Bought a new 06 Stang GT, that's enough "hot rod" for me now. Anyway, I had a Holley 600 on the 5.0 before, but the "Kid" sold it to a buddy, before going off to join the Marines. Well the guy he sold it to, likes it so much, he refused to swap it back to me for a Holley 750 (that would be a better match for his 383 Chevy ) so I had to rebuild the 750 to use on my 5.0. The 750 looked fairly new, so I tried it on the 5.0 to see if it'd work as is. Fuel went everywhere. I pulled it off, and tore it down to put a kit in it. During the teardown, I found the reason the previous owner of the 750 quit using it and put it up for sale on the used parts rack at the local speed shop. PLEASE PEOPLE, IF YOU'RE GOING TO INVEST IN A $400+ CARB, DO YOUR SELF A FAVOR AND ALSO INVEST IN A $5 FUEL FILTER. Don't bolt a Holley carb on, run it for a few months till the filter in the fuel inlet on the bowls clogs with crap, (Yea, the "rock" filter was clogged up with what looked like red mud, some of which also made it into the primary bowl) then blame the carb for it's problems, and then run out and buy a brand "E" carb to solve it. I also noticed that the red mud was conspicuously absent from the secondary side filter. Apparently, he also failed to properly tune the 750 to where the secondaries would ever open up. No point in buying a 750 cfm 4 bbl carb and then using it as a 375 cfm 2 bbl.

 

[86bluecobra]

lol. i hear yah. we had a carb on a 440 RB and the secondary's were also not set up. man that engine ran way better after we realized that it was running on 2 barrels.

 

[ashford]

hey theres one beauty to having a 750 on a 302, at cruising speeds your still running on the idle circuits. if you have a a/f ratio meter adjust the mixture till its in the green and get good gas milage(althoug youll have a bit of a dead spot at part throttle low rpm) got 25 mpg (highway of course) in my e-cammed capri, the best milage i ever got from it was with that carb. but in town just forget about efficiency.

 

[10secgoal]

PLEASE PEOPLE, IF YOU'RE GOING TO INVEST IN A $400+ CARB, DO YOUR SELF A FAVOR AND ALSO INVEST IN A $5 FUEL FILTER. Don't bolt a Holley carb on, run it for a few months till the filter in the fuel inlet on the bowls clogs with crap, (Yea, the "rock" filter was clogged up with what looked like red mud, some of which also made it into the primary bowl) then blame the carb for it's problems, and then run out and buy a brand "E" carb to solve it.

 

[jerry S]

I had a similar experience. New Holley 650 atop my totally rebuilt 351W. I had all kinds of problems with fuel delivery. The car sputtered and died out on the freeway. When I came here asking for tips, I was told that the old dizzy and ignition sounded like they were in their death throes so I replaced them ($700 in total parts) but the problem remained. Then the experts here opined that I might have a bad fuel pump so I replaced that ($150) but the problem remained. I was getting ready to ditch the carb when a shop I had the car towed to disassembled the carb and found particulate matter inside the carb. This crap was blocking the needles open. turns out that the gas tank was full of rust. They drained it and had enough rust to fill up a cereal bowl. I replaced the tank, kept the carb, and made a list of things to consider before ever spending another $1000 on parts (plus shipping) again when a $150 part would have done the job. I was *t*h*i*s* close to junking the carb for a new one and a spendy one at that.

 

[HistoricMustang]

Great advice "D". Also make sure the screen is still in the fuel inlet on the carb.

HistoricMustang
www.historicmustang.com

 

[D.Hearne]

Great advice "D". Also make sure the screen is still in the fuel inlet on the carb.

HistoricMustang
www.historicmustang.com

My "homegrown" fuel system on the Ranger has the following filters: One between the tank and electric pump, another filter/water separator after the pump, another inline filter before the regulator, plus the two "rock" filters in the carb inlets on the bowls. Recently, before I pulled the 331 sixpack, it was having starvation problems at high speeds I pulled the filter between the tank and pump (just a tip here: this is an "el-cheapo" 30 gal/hr Purolator pump feeding a 400+ horse 331 with 3 Holley 2 bbls ) This filter was the culprit, full of crap, not the tiny electric pump.

 

[D.Hearne]

hey theres one beauty to having a 750 on a 302, at cruising speeds your still running on the idle circuits. if you have a a/f ratio meter adjust the mixture till its in the green and get good gas milage(althoug youll have a bit of a dead spot at part throttle low rpm) got 25 mpg (highway of course) in my e-cammed capri, the best milage i ever got from it was with that carb. but in town just forget about efficiency.

Well, I think you still needed to tune that 750. Mine has no flat spots . Idles perfectly, runs perfectly, the motor just doesn't generate enough vacuum to open the secondaries. If it does, it does it so gently that you can't feel them. I even tried both a "black" (heavy) secondary spring, then switched to the lightest sec. spring. Virtually no difference that I can tell. The only thing I've noticed is the lack of power, but that's what you get in going from a 400+ horse motor to a 275 horse motor.

 

[wild70stang]

My Carter AFB carb also didnt have a fuel filter inlet installed when I bought my mustang, and the guy used it for daily driving without 1. Its funny when you have to rig up a fuel filter system when there wasnt one to begin with, and get to have fun being showered with gasoline when you dont have a hose clamp when you remove the fuel line. ( I was broke at the time).

 

[65ShelbyClone]

Its funny, there are tons of people who will dog on Holleys for being tempermental, hard to tune, or even downright "impossible" to tune. Many of the same people have nothing but praise for the new Carter-style carb they got and didnt have to touch. Those are the types that have no business getting inside a carb. While not rampant, I do see this more often in the forums dealing with EFI cars. My fleabay 650 still needs tuning and I'll admit I'm not that great with Holleys yet, but I do recognize that the tune is the problem and not the carb.