1406 revisited - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Patch · 09-22-2002, 06:46 PM

Okay....the fuel pressure regulator has helped some, but still was getting the black cloud. So........I took it apart and found 1/8th of a inch of silt sitting under the floats....and I also found...ae you ready for this......120 sized jets on all 4 corners!!!! I remember someone on the other thread saying he had 95's in the pri's, and 105's in the sec. 120's????? Sizes are bigger with higher numbers...right? Good grief...dont tell me they built it this way from the factory!!!
So....now I'm ordering the calibration kit....what size jets do I use? It's a 350 with a 1406 and an HEI....stock cam I believe.....
Thanks.......

Patch · 09-22-2002, 07:32 PM

I looked in Jegs just now....even up to 800 CFM, they dont list 120 sized jets...only 113's. What the?????? Any ideas? If it say's 120 on the top of the jet, then it's a 120 isn't it? There's no cross number or anything? I'm confused! Let me know what you think....thanks

71402BB · 09-22-2002, 07:41 PM

did you happen to buy this carb new or used?

Patch · 09-22-2002, 08:08 PM

It was on my Blazer when I bought it. I know it's hard to tell, but it looks as if it had never been open up. ?????? Just ordered the cal kit and a re-build kit too. Hopefully this will fix the cloud out the tailpipe. The book showed 98 for the pri, and 95 for the sec....what is everyone else running?

tom hand · 09-22-2002, 08:15 PM

When I read this it sparked a memory so out to garage I went in search of my carter strip kit. It took a while to find it because I hadn't used it in 6 years or more. Well my memory was correct, every jet had 120 on it, but it is not the size, must be part of the part number. The size of the jet is on the opposite side from where the 120 is at. They are hard to read you may need a magnifying glass to read it.

tom hand · 09-22-2002, 08:26 PM

And i forgot your main problem. The silt you see is rust. So your tank or fuel line is rusted. I had this problem on a 71 Firebird. I ran 3 inline filters and the rust would still make it to the carb. On the bird it was the fuel line. I replaced it and no more problems. I'll bet your needles and seats are leaking causeing the rich problem. Good Luck

Patch · 09-22-2002, 08:39 PM

Oh man.....that sucks. Okay....I guess when I tear it apart I'll look at the other side.....I should of known better. Man...I feel like a jack-ass...Thanks....I still need want to know what everyone else is running as far as jets.....Thanks...

Patch · 09-22-2002, 08:41 PM

Well....I dont doubt the rust theory...I do have a brand new poly tank though...so it must be from the lines. The old fuel filter was full of that crap too. So are you saying the seats are leaking because Of the rust, or just leaking?

tom hand · 09-22-2002, 09:29 PM

They are leaking because of the "silt" you see in the carb. The ones in the firebird leaked so bad because of it, it flooded out at a red light. After fixing the fuel line, I cleaned out the carb and replaced the needle and seats, no more problems. The 98's and 95's sound like a good place to start. If you look again you may have them already.

09-22-2002, 06:46 PM	#1
Patch Senior Member Join Date: Jul 2002 Location: Oak Harbor, WA Posts: 709	1406 revisited Okay....the fuel pressure regulator has helped some, but still was getting the black cloud. So........I took it apart and found 1/8th of a inch of silt sitting under the floats....and I also found...ae you ready for this......120 sized jets on all 4 corners!!!! I remember someone on the other thread saying he had 95's in the pri's, and 105's in the sec. 120's????? Sizes are bigger with higher numbers...right? Good grief...dont tell me they built it this way from the factory!!! So....now I'm ordering the calibration kit....what size jets do I use? It's a 350 with a 1406 and an HEI....stock cam I believe..... Thanks....... __________________ Patch

09-22-2002, 07:32 PM	#2
Patch Senior Member Join Date: Jul 2002 Location: Oak Harbor, WA Posts: 709	????? I looked in Jegs just now....even up to 800 CFM, they dont list 120 sized jets...only 113's. What the?????? Any ideas? If it say's 120 on the top of the jet, then it's a 120 isn't it? There's no cross number or anything? I'm confused! Let me know what you think....thanks __________________ Patch

09-22-2002, 07:41 PM	#3
71402BB now thats a true COON DOG Join Date: Nov 2000 Location: Franconia, NH Posts: 1,977	did you happen to buy this carb new or used? __________________ current project 67 402BB stout th350 3.08's with a locker. Plan on tubs 18.5's out back! (thanks Burnsman!) 71 SWB Stepside, was a 250, now is a 402 Big Block with 4 speed and 3.73's ( was crushed by a tree, bed sold, motor pulled) was my first truck!... oh well... 72 LWB 4x4 350 4-speed 3.08's posi wearing army olive drab green (SOLD!) 68 BURB 50TH LOOKALIKE work in progress, soon to have 250-I6 with a 3-speed on the tree 4.11's and posi ( currently sitting in back yard tarped awaiting time, $$$, and lots of love!) 67 1 TON- work truck 396 sm 420 4-speed, flat bed 4.57 gears "big red" (my first landscape truck, very rusty and crusty! but still gets the job done when needed!)

09-22-2002, 08:08 PM	#4
Patch Senior Member Join Date: Jul 2002 Location: Oak Harbor, WA Posts: 709	Carb It was on my Blazer when I bought it. I know it's hard to tell, but it looks as if it had never been open up. ?????? Just ordered the cal kit and a re-build kit too. Hopefully this will fix the cloud out the tailpipe. The book showed 98 for the pri, and 95 for the sec....what is everyone else running? __________________ Patch

09-22-2002, 08:15 PM	#5
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	When I read this it sparked a memory so out to garage I went in search of my carter strip kit. It took a while to find it because I hadn't used it in 6 years or more. Well my memory was correct, every jet had 120 on it, but it is not the size, must be part of the part number. The size of the jet is on the opposite side from where the 120 is at. They are hard to read you may need a magnifying glass to read it. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

09-22-2002, 08:26 PM	#6
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	And i forgot your main problem. The silt you see is rust. So your tank or fuel line is rusted. I had this problem on a 71 Firebird. I ran 3 inline filters and the rust would still make it to the carb. On the bird it was the fuel line. I replaced it and no more problems. I'll bet your needles and seats are leaking causeing the rich problem. Good Luck __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

09-22-2002, 08:39 PM	#7
Patch Senior Member Join Date: Jul 2002 Location: Oak Harbor, WA Posts: 709	Oh man.... Oh man.....that sucks. Okay....I guess when I tear it apart I'll look at the other side.....I should of known better. Man...I feel like a jack-ass...Thanks....I still need want to know what everyone else is running as far as jets.....Thanks... __________________ Patch

09-22-2002, 08:41 PM	#8
Patch Senior Member Join Date: Jul 2002 Location: Oak Harbor, WA Posts: 709	New tank Well....I dont doubt the rust theory...I do have a brand new poly tank though...so it must be from the lines. The old fuel filter was full of that crap too. So are you saying the seats are leaking because Of the rust, or just leaking? __________________ Patch

09-22-2002, 09:29 PM	#9
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	They are leaking because of the "silt" you see in the carb. The ones in the firebird leaked so bad because of it, it flooded out at a red light. After fixing the fuel line, I cleaned out the carb and replaced the needle and seats, no more problems. The 98's and 95's sound like a good place to start. If you look again you may have them already. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

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