smaller carb spacer or air filter

[ScottNM]

My newly installed 468 with Edelbrock RPM intake, 1" carb spacer and 3" air filter set up is kinda pressed hard under the hood. I suppose it has an adverse affect on the filter. I live at 6k altitude. My builder wanted me to use the 1"spacer but I think he is ok without it. What would you do? I think i am going to order a 1/2" spacer and keep the filter. THe filter does have a 1 5/8 recessed bottom to it. The other thing is maybe a 2 1/2" filter. Your input is appreciated. Not ready for a cowl hood.

[72 LS5]

Is your carb a Holley and does it have a choke horn? A drop base with a 3 inch filter may be putting your lid right on the choke horn.

 

I think I'd rather have no spacer and no restriction above the carb than the reverse. Does the spacer have any dyno proven performance increase? I don't think a 2 1/2 filter will give you the breathing a 468 needs.

 

Some say the best drop base is the L88 sold by some Corvette resto companies - it has the deepest drop and best design.

 

Also Wix sells racing filters in 1/4 inch increments for a 14 inch open element. For me, a 4 inch was pushing hood clearance and 3 was a little stubby, so I settled on a 3.75 inch Wix filter with a drop base and Holley with no choke horn on an RPM air gap.

[Big Jim]

Does the spacer have the vacum port for brakes?

[ScottNM]

Its a 770 holley street avenger carb. There is not other holes for brake vac. There is a 3/8" phenolic spacer in town. I think the 5/8" extra should relieve pressure against the air cleaner.