open or 4 hole

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Ironmike

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Well, I feel a little strange. Just installed the first dual plane manifold I have EVER put on one of my hot rods.
Took off the Weiand X-Celerator and put on an Air gap. My smallblock "you know what" buddies tell me they're getting just as much top end as the old Torker, with way more bottom end and driveability. So I took the plunge.

My question is: Looking at my Holley carb gasket, it appears to me that I need to use a 4 hole type instead of the open square ones I have now. I'm thinking with the dual plane Air Gap, the 2 sides of the carb should definitely be sealed to they're perspective side of the manifold. Wouldn't boltin on the carb with an open gasket more or less defeat the purpose of a dual plane intake?

Waddayathink? Am I crazy...or right?
 
The only time I would use a 4 hole is if I run (and I do) a single plane, it helps the bottom end and for help keeping the heat from the carb.
 
There's no need to keep each side sealed and you probably don't want to either. An open plenum will help balance out the pulses inside the intake and make for a smoother running engine.
 
I have tried both on my Air-gap and the open spacer ran worse than no spacer at all. An open 1/4" thick gasket also seemed to worsen performance just like the open spacer. The 4 hole definitely picked up some torque and didn't seem to loose anything up top. Whether or not a spacer will make your car run better depends on your engine requirements. A certain amount of runner length and plenum volume is required for each individual engine so going away from that only hurts power output. In other words a spacer, whether open or 4 hole does not always help as some guys claim. Why don't you first try it with just a gasket and no spacer rather than try to re-invent the wheel? Then experiment from there.
 
Wait, I'm confused a bit, let me get this striaght.

Your worried about defeating the purpose of a dual plane intake with the use of a open gasket to seal the carb down? A 1/16 inch gasket?
 
fishy68 said:
I have tried both on my Air-gap and the open spacer ran worse than no spacer at all. An open 1/4" thick gasket also seemed to worsen performance just like the open spacer. The 4 hole definitely picked up some torque and didn't seem to loose anything up top. Whether or not a spacer will make your car run better depends on your engine requirements. A certain amount of runner length and plenum volume is required for each individual engine so going away from that only hurts power output. In other words a spacer, whether open or 4 hole does not always help as some guys claim. Why don't you first try it with just a gasket and no spacer rather than try to re-invent the wheel? Then experiment from there.
Click to expand...

yep.

Big picture=app/combo dependent.

I run a 3/8 spacer on my 340 w/ old weiand single plane and it picked up after 4000rpm and pulled a lil longer/higher in the r's
 
the OP isnt asking about a carb spacer, he asked about the carb to manifold gasket.
Use a gasket that matches the intake, ie: 4 holes in the intake=4 holes in the gasket, 1 hole in the intake=1 hole in the gasket, etc.
 
Jimacuda said:
the OP isnt asking about a carb spacer, he asked about the carb to manifold gasket.
Use a gasket that matches the intake, ie: 4 holes in the intake=4 holes in the gasket, 1 hole in the intake=1 hole in the gasket, etc.
Click to expand...

Your right. I mis-read it. Sorry IronMike for the confusion.
 
I would use the 4 hole just so if the screw in the bottom of a holley carb comes loose it doesnt make its way through the engine.
 
I never heard of that screw coming loose.

The gasket, open hole or 4 hole, won't make a difference in the performance of the engine or diminish the intakes performance or operation in anyway.
 
I'm nearly positive all the base screws are covered up on a Holley by the base gasket. They don't use a center screw. Just screws around the perimeter. I did see it happen to a Quadrajet on a Pontiac 400 with a single plane intake. Wasn't pretty.
 
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