Help with loading up and does a thicker airhorn gasket affect hanger selection?

[davel]

Guys, I'm new to the forum and have been getting lots of great information here. Thanks much for that!  I also own a copy of Cliff's Q Jet book but unfortunately my brother absconded with it. Blast! I'm going to need another copy...

So I recently built a 383 for my 77 K5 Blazer and thought I'd post my Q-Jet experience with that motor and ask a couple questions to the experts.  Here goes.

The Engine:
383 sbc stroker, 190cc runner aluminum heads, 9.6:1 CR, Howards roller cam 217/225 @ 0.50" - 0.530" lift - 108 deg LSA

The Truck:
1977 K5 Blazer, SM465 manual tranny, 3.08:1 diff, 31 X 10.5 tires (70mph @ 2500rpm in top gear) 4500lbs with me and a tank of fuel.

The Carb:
Jet Modified Stage 2 Q Jet, PN 17081226 (0861 DDS). 73 Main Jet (not sure about the primary rods), DA secondary rods, "I" hanger.  This is how the carburetor was setup by Jet.

So here's the issue: The primary circuit seems to be dialed in perfectly.  But when the secondaries open at low RPM and the engine is under strain - up an incline in top gear - the engine will load up between 1700 and 2000 rpm.  So imagine you're in top gear going up an incline at 35mph. The engine's at 1200rpm. Then and you put your foot all the way to the floor.  The engine will pull cleanly until about 1700 then it loads up. It sounds like WOP WOP WOP until you back out of the throttle.  If you stay out of the secondaries until the engine reaches 2100rpm and put your foot back on the floor, it'll pull clean and strong all the way to red line. 

First I adjusted the air door tension spring and it did little to nothing.  I happen to have some old hangers laying around so I started playing with them.  I have a "K" an "M" and 2 "S" hangers.  The holes in one of the "S" hangers are egged out so the needles sit approximately 0.030" lower than the other "S" hanger.  (I'm not sure if it's worn out or someone filed the holes)  I started swapping out hangers and the leaner I got with the hanger the better it ran. Now it seems to run perfectly when using the "S" hanger with the egged out holes!  There's no loading up and the transition between circuits feels seamless.

So I have 2 questions:

1) This carburetor has the thicker (0.060") air horn gasket.  I believe the factory gasket is 0.030" thick.  Does the thicker gasket affect hanger selection? Wouldn't it be necessary to run a 0.030" leaner hanger if you switch from a factory gasket to a thicker gasket?

2) If the first answer is YES then effectively the combination I'm running is DA secondary rods and an "S" hanger.  Does that seem like the right setup for this combination?  Would it be better to run a different rod with a richer hanger?  In other words, with the current setup, am I overcompensating for a rich condition at low RPM and hurting high RPM performance in the process by running with a lean hanger?

Thanks!
Dave

[davel]

Here's a pic of the egged put "S" hanger I'm currently running.  Engine definitely likes this hanger the best. haha 

[Ethan1]

 Do you have a "V" hanger. You have the dreaded reman carb. I think you might have more problems than just the hanger. 

[davel]

Hi Ethan,

Thanks for the reply.  Unfortunately, I don't have a "V" hanger though it seems that would be similar to what I'm running currently with the worn out "S" hanger.  Do you think I should just run with a "V" hanger and these DA rods or try switching to a leaner rod like a CK and a richer hanger?

Or I could hedge my bets and pickup a "V" hanger AND a set of CK rods.  What do you think?  Does Cliff stock those parts?

[Ethan1]

Hi Ethan,

Thanks for the reply.  Unfortunately, I don't have a "V" hanger though it seems that would be similar to what I'm running currently with the worn out "S" hanger.  Do you think I should just run with a "V" hanger and these DA rods or try switching to a leaner rod like a CK and a richer hanger?

Or I could hedge my bets and pickup a "V" hanger AND a set of CK rods.  What do you think?  Does Cliff stock those parts?

 Hey Dave,
 Yeah, you could try that. That would lean out the secondary side a little. I would keep your "S" hanger for now, but I wouldn't use it long as it has been "modified". You don't know what height the secondary rods are set at. Kind of a guessing game. Look for a "V" hanger. Cliff, should stock them. eBay carries them, too.

http://www.ebay.com/itm/Rochester-Quadrajet-Secondary-Metering-Rod-Hanger-Stamped-V-Dimension-H-615-/172197013634?hash=item2817bde882:g:4wMAAOSwt7pXLVUG&vxp=mtr

[von]

Why mess around with different hangers when you can easily bend them to change the rod height?