I think I have a vacum leak. I have eratic idle issues and lack of power and bad vibrations. It all stared when I switched carburetors. I think it might be in the carb-adapterplate-manifold. Im going to spray it with carb cleaner in the morning like Ive been told to do.

Other things I can think of (So let me know if anything is obvious that Im missing)

On the back of my adapter plate theres a threaded hole that goes to nowhere. Its just a little threaded hole . I thought it might have been a vacum secondary but if you plug it up with your finger it doesnt channge anything.
When I switched carbs I didnt have any vacum line so I used fuel line to hook up my power brake booster. Thats not a problem right. ... right.
If it is inbetween the carb and adapter plate what can I do about it. New Gasket? Thicker Gasket?


Thanks in advance for any help.

 

the hole in the adapter plate, is it for the correct baseplate on your carb? for example stock gm intakes require a spreadbore carb like the q jet. some holleys are squarebore which needs the adapter. are u sure u go the correct one? if so plug the hole on your adapter plate. then spray some carb cleaner around there. it might solve your problem. make sure u have the correct adapter plate though.

 

What do you mean? Im not completely familiar with the lingo of carbs t manifolds. Are you talking about just the bolt pattern or the size of the plate or wether or not theres 4 holes or just one big square opening or what. Another words Dummy it down for me a little.

 

well if u have a stock gm or aftermarket "spreadbore" intake, a spreadbore carb like a qjet will mount without a prob. if u have a spreadbore intake and a sqaurebore carb u need an adapter to mount the squarebore carb to the spreadbore intake. if your adapter is wrong then that might make your problem. u might have a spreadbore intake and carb. or a squarebore intake and spreadbore carb and visaversa.

 

But whats the difference between Square bore and Spread bore? The Bolt pattern or just the shape of the plate itself.

 

sorry i wish i could tell u that one. i would venture to say the actual base plate is different.

 

Here's a pic of a manifold (ZZ4) that's equipped for both square-flange and spreadbore carbs. This one wouldn't require an adapter plate. The inner set of stud holes is for spreadbore, the outer ones for square. The secondary end of the holes is bigger, to allow for the larger throttle bores of a spreadbore carb.

A vacuum leak will generally not cause a lack of power. It will make the motor run terrible whenever the vacuum is high, i.e. idle or cruise; but has progressively less and less effect the lower the vacuum is, i.e. the farther you open the throttle.

I'd look for a loose or damaged plug wire first; easy to disturb those during a carb swap.

 

Thank you for the Clarification.
Nah Ive triple Checked the plug wires. Im going to replace the cap and rotor today because that hasnt been done since I bought it. Thanks.