Holley/Demon Carb stumble
Idle feed slot with 1.687 gasket(which is what was installed in carb) on baseplate (hole lines up with slot):
Idle feed hole of 1.687 gasket on main body(as you can see, the gasket completely blocks off idle feed hole in body):
If you look at the previous pic showing the bottom of the carb with no gasket, you can see there is a slight counter bore at the bottom of each barrel.
The OD of the counterbore is the size of the 1.750 gasket.
When the 1.750 gasket is used, the idle hole in the body lines up with the gasket, and the baseplate:
I dug thru a bunch of gaskets to see if I had something that had a 1.687 bore, but had the idle feed holes either slotted, or in the 1.750 position...... but I didn’t have anything like that on hand(it may exist and I just don’t have any).
This carb is getting put back together with the 1.750 gasket(considering the counterbore, this is probably the “correct” gasket for this carb).
I’m glad I looked!!
The only reason I can think of for the idle feed hole in the baseplate to be slotted is if perhaps the smaller BG carbs of that era had the idle feed holes in the body located in the normal 1.687 location.
Then this baseplate would still work.
As it is, it would work with a Holley/Proform/QFT main body that used a 1-11/16” baseplate.
Idle feed slot with 1.687 gasket(which is what was installed in carb) on baseplate (hole lines up with slot):
Idle feed hole of 1.687 gasket on main body(as you can see, the gasket completely blocks off idle feed hole in body):
If you look at the previous pic showing the bottom of the carb with no gasket, you can see there is a slight counter bore at the bottom of each barrel.
The OD of the counterbore is the size of the 1.750 gasket.
When the 1.750 gasket is used, the idle hole in the body lines up with the gasket, and the baseplate:
I dug thru a bunch of gaskets to see if I had something that had a 1.687 bore, but had the idle feed holes either slotted, or in the 1.750 position...... but I didn’t have anything like that on hand(it may exist and I just don’t have any).
This carb is getting put back together with the 1.750 gasket(considering the counterbore, this is probably the “correct” gasket for this carb).
I’m glad I looked!!
The only reason I can think of for the idle feed hole in the baseplate to be slotted is if perhaps the smaller BG carbs of that era had the idle feed holes in the body located in the normal 1.687 location.
Then this baseplate would still work.
As it is, it would work with a Holley/Proform/QFT main body that used a 1-11/16” baseplate.
