Carb help

[ZZ4Blazer]

Looking for any help or suggestions on carb mods.

94 s-10 with mild 350, 750 carb with proform main body.

On fast corners(just on the street, and not pushing really hard. dont wanna find the limits of my truck out on the street), the engine will bog, and I believe Im forcing gas out of the carb boosters and flooding the engine.

Same with hard braking. If I really try stopping it hard, it'll die. Seems same problem.

Runs pretty well with just the minor tuning I've done. Good AFR's cruising, and WOT. Timing's at 14 idle, 35 total. Starts right up, and good throttle response. Bowls are adjusted right, jet extentions on front and rear, and bowls are baffled. Tried a vent tube crossover, made no difference, so I know Im not forcing gas out the vent tubes into the body.

Any suggestions? Or is there really a limit on corners with a carb? I cant see my truck being at that limit already with the mods I've done.

[Shaker455]

Jet extensions are "NOT" for street use nor are they intended to be used in the mannor your attempting.

I'd advise you to remove them.

[ZZ4Blazer]

They were added a while back to help with hard braking on the fronts. Helped, but didnt notice any difference in driving other than that. Trucks a lot more modified now. I'll yank the fronts out and give it a whirl.

[sporter]

Been there done that. My Holley's worked great on the street for over 25 years without too much trouble until I ran them on a car that had modern brakes (13"/12" discs with hydrabooster) and modern handling (SC&C UCA, 17" wheels, etc). After that my Holley's just flat sucked during low speed hard braking maneuvers. Tried everything the Holley tech guys advised, but nothing totally eliminated the problem.

However, you may as well try to isolate the problem. Disconnect the fuel line to your rear bowl, plug the line and drain the rear bowl. Now drive it and see if you have any change in braking and cornering. If the problems go away, it's your rear bowl. If not, the problem is in your front bowl. All of my problems were due to fuel running from the rear boosters during deceleration.

If you want to see what's happening with your carb, remove it and mount it on four bolts like you're rebuilding it. Place it in a large pan and fill the bowls to spec. Have someone drive you around while you observe your boosters. I found my regular boosters behaved the best, the dog leg boosters lost more fuel and my annular boosters leaked like crazy under even moderate g's.

BTW, I eventually gave up on Holley's for street use due to these reasons. Qjets are simply superior in terms of fuel control during all decel high g's and most accel high g's. Please post if you find a fix for this problem.

[ZZ4Blazer]

Thank you for your help. Im leaning towards the rears being most of hte problem. I've noticed that the rear butterflies will be wet, even if I havent had the secondaries open.

She's not a vette, but will suprise most people with my truck. ATS tall spindles, hotchkis arms & matching sway bars, QA1 coilovers, hydratech booster, 14" C6Z brakes wrapped in 18" BFG rubber.

Unfortunately, I'll probably end up going with a mpfi. I know right now it seems Im past the edge of the carb. And its only getting more modded from here.

[My427stang]

How do you set your float level?

[ZZ4Blazer]

I have my floats set a hair below where they should be. As per holley instructions, they should be set just at the bottom of the plug.

I have mine set just below that. Seems to help having it just lower than that. I dont wanna go any lower, and risk running the bowl empty on a long straight away.

[My427stang]

Well you are probably a little low, I sure wouldnt go lower,

Holley float level is as much a tuning aid as any other part of the carb. Those instructions are merely a place that everyone can get their motor running

As you raise or lower, its tougher or easier for the siphon to pull through each circuit. Its most prevalent on the transition circuit.

That doesnt mean that IS your problem, however, although I wouldnt venture to guess that your primaries with jet extensions could be coming uncovered at acceleration and maybe causing half of your problem overall

Next time you play with it, I recommend raising the float level front an back about 2-3 flats of the nut if that makes sense. It should readily, but not crazily come out of the hole when you take the plug out.

However, I have had cars with fussy intermediate circuits that I even go higher than that. Like I said, just another tuning tool.



I personally dont like jet extensions unless there is no other choice. I would pull them out of there myself, especially on the front