I am going to rework my PCV, brake booster and vacuum advance hoses. The goal is to use the intake access for brake booster and vacuum advance, and run the PCV to the rear of the throttle plate. Note this carb does not have vacuum ports, just the one large inlet at the bottom rear into the throttle plate, the others are plugged and staked.
Engine is a SBC with dual plane air gap intake and double pumper Holley carb. The way this fits together there is very little room for accessing the vacuum port on the intake. There is right at 1/2" between the intake and accelerator pump - not enough room for a fitting. Height is a concern, air cleaner is basically touching the hood insulation right now. I do have a drop base air cleaner and using 3" element. Car has a SS hood, I can cut out the insulation above the air cleaner to create a little more space (I think the SS hood has a little room above the insulation). Not interested in swapping to a cowl hood.
I know I have a few options, carb spacer, shorter air filter etc... current plan is to add a 1/2" or 5/8" carb spacer and use 2-1/2" air filter element (or see if the insulation removal creates enough space to keep the 3"). I am concerned about the shorter element restricting air flow - it is hard to find flow rates for air filter elements... I haven't had much luck finding an ultra low profile adapter with hose barbs to fit the intake - this would be the best solution.
I am sure this issue has been discussed before, but I didn't turn up much in my search. Any other ideas? Or anyone know of a low profile vacuum fitting?
Here is a picture of what I am talking about:
![Image]()
Engine is a SBC with dual plane air gap intake and double pumper Holley carb. The way this fits together there is very little room for accessing the vacuum port on the intake. There is right at 1/2" between the intake and accelerator pump - not enough room for a fitting. Height is a concern, air cleaner is basically touching the hood insulation right now. I do have a drop base air cleaner and using 3" element. Car has a SS hood, I can cut out the insulation above the air cleaner to create a little more space (I think the SS hood has a little room above the insulation). Not interested in swapping to a cowl hood.
I know I have a few options, carb spacer, shorter air filter etc... current plan is to add a 1/2" or 5/8" carb spacer and use 2-1/2" air filter element (or see if the insulation removal creates enough space to keep the 3"). I am concerned about the shorter element restricting air flow - it is hard to find flow rates for air filter elements... I haven't had much luck finding an ultra low profile adapter with hose barbs to fit the intake - this would be the best solution.
I am sure this issue has been discussed before, but I didn't turn up much in my search. Any other ideas? Or anyone know of a low profile vacuum fitting?
Here is a picture of what I am talking about:
