Holley float level sight plug holes
 

I bought two new float bowls for my Holley 4150 double pumper and installed tham only to discover that the location of the float bowl sight plug holes is different, from the front bowl to the back one. Is this anything I need to address, or more to-the-point, why would they be at different heights? What am I missing here???

Anybody got any ideas on this?

Any information will be appreciated!

Re: Holley float level sight plug holes
 

Just use a 3/8ths drill with the bowl up side down. Seems as I remember there was a difference between the 4150 & 4500 bowls. Are the ones you got drilled and tapped on both sides of the fuel inlets? If they are they are 4500 bowls.

Re: Holley float level sight plug holes
 

I agree. I don't think serious racers use the sight plugs anymore. We didn't in the '70s.

Re: Holley float level sight plug holes
 

Ed,

I'm not a serious racer (as you know,) but neither do I want to run around with float levels maladjusted. I didn't know an alternative way to adjust them...

Thanks for the info.

Re: Holley float level sight plug holes
 

Yes, I had to move the inlet to the other side of the carb for the applicatiion, so I just bought two new bowls. One of the new bowls has threads on both sides of the fuel entrance. I guess that's the 4500 bowl...

Thanks for the explanation!

Re: Holley float level sight plug holes
 

They are supposed to be different heights. At least thats they way Holley makes them.
I believe the secondary is higher than the primary.

Re: Holley float level sight plug holes
 

Thanks for that bit of information! I learn SOMETHING new, every day... :)

Re: Holley float level sight plug holes
 

I always use a 7/16" drill bit as a gauge for the primary (front) and 3/8" for the secondaries.

Re: Holley float level sight plug holes
 

Thanks, Ed; I am sure that's good advice! I'll follow it!!!

Re: Holley float level sight plug holes
 

If its a square carb like a 750 same pri & sec vent and throttle blade size I make everything same float levels air bleeds and jets same

Re: Holley float level sight plug holes
 

Ralph; it IS a 750... double-pumper with 4-corner idle jets. Going on a high-boost, turbocharged slant 6....

Thanks for the advice!!!


Bill

Re: Holley float level sight plug holes
 

A good starting point with no Power valve is
Mj 77 or 78
HS bleed .026
Idle bleed .067 or .070
Idle feed rest in metering block .036 to .039
Set idle so blades are just below transfer slot.
At least .070 holes in throttle blades

Re: Holley float level sight plug holes
 

Are you doing the Hanger 18 mods to the carb?

Re: Holley float level sight plug holes
 

Harry,

I had a friend of mine who has a successful turbocharged 225 slant six in a '70 Dart (11-flat at 122 mph running into a 15-mph headwind, at 3,300-pounds,) modify this carb for me for blow-thru, and I am not aware of what he did, beyond building a bracket that was needed, for some reason, to locate a boost-referenced power valve. The primary float had to be relieved, somewhat, to clear that bracket.

I am sorry I don't know more to tell you. I am not familar with the "Hangar 18" mods, whatever they might be. Can you enlighten me please?

Thanks for your interest!

Re: Holley float level sight plug holes
 

Thanks Ralph.

This carb has a boost-referenced power valve that will be operational.

The cams for these turbocharged engines have very little duration (210/210-degrees @ .050"-lift,) and are ground with 115-degrees of lobe separation, so they idle like a stocker.

I guess turbo engines don't much like overlap...

I don't think that I'll need any holes in my throttle butterflies, will I???

Thanks for any information!!!

Re: Holley float level sight plug holes
 

Hanger 18 mods are just removeing the air horn, plugging holes, making replacable jets for your pvcr's so can you run a smaller jet, some people just drill them out but it works better if you have jets of different sizes. I made mine out of 10-32x1/4" brass allen head set screws. The slant six can put out some real good power with a little boost. How big can you make a 225? I currently have a turbo'd 292 chevy six that I'm trying to get ironed out. Should be fun.

Re: Holley float level sight plug holes
 

Thanks Harry.

Can we take this discussion to email? I am sure there Class-Legal guys aren't interested in all this hairdryer conversation.

Email me at Billdedman@hotmail.com and I'd love to discuss this with you, and send you some pictures, email.

Thanks,

Re: Holley float level sight plug holes
 

It will just depend on if you can get idle speed correct with out exposing transfer slot set the secondary with the screw from the bottom side don't expose anymore than .060 of the transfer slot. If you can't get your wanted speed get your drills out.
Ralph


QUOTE=bill dedman;332354]Harry,

I had a friend of mine who has a successful turbocharged 225 slant six in a '70 Dart (11-flat at 122 mph running into a 15-mph headwind, at 3,300-pounds,) modify this carb for me for blow-thru, and I am not aware of what he did, beyond building a bracket that was needed, for some reason, to locate a boost-referenced power valve. The primary float had to be relieved, somewhat, to clear that bracket.

I am sorry I don't know more to tell you. I am not familar with the "Hangar 18" mods, whatever they might be. Can you enlighten me please?

Thanks for your interest![/QUOTE]

Re: Holley float level sight plug holes
 

That soinds like a plan, Ralph!!!

Not a street car at all; just trying to get it from point a to point b in the shortest time possible, so driveability is not an issue here.

Thanks much!!! :)