So I've had the S10 out recently...88 4.3 500 edelbrock h1c turbo hei locked distributor. Was running real good one day and my plastic spacer between the carb and the hat decided it no longer wanted to be there. Popped under 8 or 9 lbs and I thought she was done for! Well fortunately I was wrong. Replaced it with an aluminum spacer and when I tightened the carb hat twisted it about 5 degrees more off center than it was. It gave me a bit more clearance around the belt bracketry. Drove it down the road and it ran good until it got into boost. Then it went waaaayyy lean and was like you shut the key off until you released the throttle. Looked over everything today and said what the heck is going on? Then I decided to rotate my carb hat back to where it was...fixed it. Ran the same as before. Now I know that optimum placement is straight on top of the carb especially with the divider inside the hat, but my serp belt bracketry won't allow that. I'm debating whether it would be worth spacing the carb up to clear that and reroute tubing would be worth doing? I can imagine I will have to return the carb once I do but maybe it will free up some power and more economy since it would eliminate the offset divider. Or would i be better off with a hat without the divider? Any thoughts would be appreciated! Thanks in advance! Also included a pic of how it sits when it runs good.
Joel

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I would start with spacing the hat up off the carb, with the hope that this gives the air a chance to calm down and mix a little. This is a known problem with carb hats, the divider was one design idea to help it. Unfortunately re tune is probably required no matter how you solve it.

 

At one time I did space it up higher and I remember it doing the same thing. At that time I didn't change the angle much because having it higher gave me alot more clearance. After driving it and it acting funny I actually put the thinner spacer back in and blamed it on turbulence due to it being spaced up higher. Maybe that was the wrong answer but seemed logical to me at the time. I often wonder if dividing the spacer the same as the hat would help as well with cutting down the turbulence. Maybe I'll look for a metal spacer around 2-3 inches high and try to straighten the hat and make a new intake pipe from the turbo to the hat...the one I made first I a kinda ugly anyway!
Joel

 

Turbulence is for sure a problem, so are the high velocity air areas and air distribution. Essentially all the barrels of the carb aren't seeing the same thing at every venturi like it would be if it was NA. It can be tough to solve. Playing with entry angle could help, 4 corner tuning the carb could help.

Is this a dual or single plane manifold?

 

It's an edelbrock 2111 I believe. It is called a dual plane by edelbrock but it's more single plan like by design. Each side is open right to the ports for the most part and it has a center divider that doesn't go all the way up. The ports are real short especially the rears due to the intake itself being so short for the v6. I would say the carb is actually lower than the factory tbi intake was. Not alot of availability for a different intake unless you get into custom made or one of the old GM cross ram styles they used for Busch series way back when, but they don't pop up too often and when they do they're pretty pricey. I guess I'll just have to play with it and see if I can straighten the hat out with a higher spacer and maybe even try a divider in the spacer to see what happens.
Joel

 

It could be the way the air flows across the vent tubes .
I have not played with angles alot. Ive ran 1 inch spacers on all the 90 deg style hats like this. Everytime it leaned out because it put the vent tube below the inlet and caused the primary to have irregular bowl pressure in reference to the remainder of the carb. So I just add an extention to put the vent to in the path of air flow.

Something to consider. The air is always going to flow faster on the back side radius of the hat. With a divider it will physically move air so fast to the rear/long side turn, that it will starve the primary of air causing all sorts of bullshty. With an open hat it will still do this but, being open it will balance it out some.

 

Inside the hat I made covers to block off the vents over top of the primary metering rod covers. The vent tubes protrude into the intake pipe facing towards the turbo. If I recall they are inside the intake pipe around 3 inches or so. I just made s bends and tacked them to the sides of the tubes and then sealed with JB Weld. First time I fully welded them and they broke off right at the weld they were real brittle. So maybe I should just try to put the spacer in and skip the divider for now and see how it turns out. I can always add it later if it doesn't work the way I think it should! Thank you guys for the input! I'll keep you posted on how it turns out!
Joel