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Need help with intake for Pontiac big chief heads

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dcrumlich

New Member
Jul 14, 2009
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Well, I figured from all of my NHRA SG and SC days, you guys are the most creative racers out there.

I have a 605" with the pontiac 427 heads 18 deg big chief, 10.2 deck. I currently have a shorter tunnel ram with two 1150 on it. I run a lot of racing that i have to slow the car down, index type. When I throttle stop, the car hates it.

I really would like to have a single carb on it. We made a single top with about a 2" rise to it. The center cylinders took all the fuel and the outer ones were way too lean and would never fatten up no matter how much fuel we put to it. The motor would pulsate bad until I gave the run up.

Is there a thought of how to defect the fuel charge to the outer cylinders with this top?

I tried to get a edelbrock 2984 for it. They are out of my budget and hard to find.

Another thought was to modify an existing intake availible today, by filling in and opening to get the right spacing. Has anyone ever done this? If so, what intake is closest to the pontiac spacing.

Any ideas would be helpful. I figured you guys ran these years ago and might know.

Thanks
 
dcrumlich said:
Well, I figured from all of my NHRA SG and SC days, you guys are the most creative racers out there.

I have a 605" with the pontiac 427 heads 18 deg big chief, 10.2 deck. I currently have a shorter tunnel ram with two 1150 on it. I run a lot of racing that i have to slow the car down, index type. When I throttle stop, the car hates it.

I really would like to have a single carb on it. We made a single top with about a 2" rise to it. The center cylinders took all the fuel and the outer ones were way too lean and would never fatten up no matter how much fuel we put to it. The motor would pulsate bad until I gave the run up.

Is there a thought of how to defect the fuel charge to the outer cylinders with this top?

I tried to get a edelbrock 2984 for it. They are out of my budget and hard to find.

Another thought was to modify an existing intake availible today, by filling in and opening to get the right spacing. Has anyone ever done this? If so, what intake is closest to the pontiac spacing.

Any ideas would be helpful. I figured you guys ran these years ago and might know.

Thanks
Click to expand...

How do you have the runners set up in the plenum? Do you have them on the 4 corners? I know in the Victor intakes, you will see baffles extending out from the runner entry ports splitting the area between the entry ports.
 
The intake is a shorter sheet metal type. The runners are in pairs spread out to the corners.

The single top we made is only about 2 inches in total rise in the center. I was thinking i could put a ramp to the front and back to direct the fuel mixture to the middle of where the two carbs would sit.

I will try to load some pictures tonight
 
dcrumlich said:
The intake is a shorter sheet metal type. The runners are in pairs spread out to the corners.

The single top we made is only about 2 inches in total rise in the center. I was thinking i could put a ramp to the front and back to direct the fuel mixture to the middle of where the two carbs would sit.

I will try to load some pictures tonight
Click to expand...

That would help a lot.
 
You think the ramp idea would help? I thought it would be worth a try to deflect the charge front and year instead of it falling straight down into the center runners.
 
Last edited:
dcrumlich said:
You think the ramp idea would help? I thought it would be worth a try to deflect the charge front and year instead of it falling straight down into the center runners.
Click to expand...

I don't think it could hurt. You need to baffle the intake flow somehow, until you do, the center 2 cylinders on each side will continue to get all the fuel and air because it will always travel the path of least resistance.
 
Ed,

That was one thought i had to either run smaller dual carbs or some 500 cfm 2 barrels.

But i found the edelbrock intake that they made at least 15 years ago. It is 10.5 inches tall and made for a single dominator.

So next weekend we will try it.

Thank you all for your ideas.

Doug
 
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